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• How to stop Firefox on an SSD from freezing when using the search box or submitting a form?

  - by sblair

  Firefox usually freezes for about a second whenever I search for something from the toolbar search box, when submitting a form, or when clearing the search box history. I suspect it has something to do with the auto-complete feature. Using Windows 7's Resource Monitor, the problem seems to be from the file: C:\Users\<username>\AppData\Roaming\Mozilla\Firefox\Profiles\<profile>\formhistory.sqlite-journal I believe this is a temporary file which caches database writes. The following screenshot shows the very high response times from six different searches, and that the queue length on drive C shoots off the scale: My Firefox profile is on an Intel X25-M G2 SSD. The problem doesn't seem to occur if I create a new profile on a hard disk drive. However, I'd like to know why the problem exists on the SSD in the first place (because it's an annoying problem which contradicts the reason I bought an SSD, and it might happen with other applications too), and how to prevent it. It still occurs if Firefox is started in safe mode, and with the recent beta versions. Updates: VACUUMing the Firefox profile databases does not help with this problem. The SSD Optimizer in the Intel SSD Toolbox does not help either.

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• Background process text appears in terminal vim

  - by Jezen Thomas

  First time poster, long time lurker, searched, couldn’t find etc, etc. I’m running vim in tmux, in iTerm2. I’m running a server with Grunt.js, which I have running in the background, out of my way. I start my grunt server in the background like this: grunt server & Grunt also watches a bunch of files, and runs some tasks when any of the watched files have been written to. The problem is, when I am in vim and I write a file, the output from grunt starts rendering in vim! Here are some screenshots to illustrate the problem: Before writing the file: And after writing the file: What have I tried? I’ve tried running a ‘stock’ vim by starting with this: vim -u NONE …But the problem remains. This suggests to me that the problem is not with my .vimrc. Perhaps it’s an issue with iTerm2, I don’t know. Help.

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• Chrome and Firefox freeze when I begin typing

  - by mschulze

  Last night, chrome began freezing whenever I tried to type anything. After a fresh reinstall the problem went away but it is back again this morning. I installed Firefox as a substitute browser but it has the same problem. I cannot even get past the homepage because typing in the u r l bar freezes both programs. Last night internet explorer froze once too, but it has not happened since. Disabling shock-wave does not have any affect on the problem. Because it is happening across multiple browsers, I do not believe it to be caused by any extensions I have installed on Chrome. I also tried running Chrome as a new user and the problem still occurred. I can open any apps or web sites that are on my homepage, but as soon as I try to type anything the program freezes. Any ideas?

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• Tree structured troubleshooting survey which gives solution based on answers

  - by japie1001

  Is there some online tool which let me design a tree structured questionaire/survey which suggests a solution to a problem. Example troubleshooting survey for the problem of black monitor screen: Q1: Is the powercable connected to the monitor? 0 Yes 0 NO If answer is no: "The solution to your problem is to connect the power cable" If answer is yes: Contiue with Q2 Q2: Is the computer turned on: 0 yes 0 no etc Is there something like Google Forms where I can achieve this with online?

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• Sudden and frequent hangs on desktop computer: mobo or CPU fault?

  - by djechelon

  I have a desktop computer equipped with an ASUS Crosshair 2 Formula and a Phenom x6 3.2GHz CPU. My problem is that often the computer will hang all of a sudden, completely stopping responding. When that occurs, reset key is inoperative and power button turns the computer off but is unable to turn it back on. I have to physically disconnect power cable. The problem can occur anytime, when I'm booting Windows, when I'm logging in, when I'm listening to a song, when I'm browsing Internet, etc. It always occurs after very few minutes of 3D gameplay I thought it was a video card fault. I had 3 8800GTX so I could try all combinations of them: didn't fix I thought it was a RAM problem: I tried running with only a subset of my DDR2 banks but didn't fix. Almost every time I have to reset and reconfigure BIOS (without AHCI, Win7 won't boot, so I need to restore a few things). If I enable AMD Live, Cool&Quiet or other things from CPU configuration menu I'll be sure that the computer won't reach Windows desktop in 99% of cases (it randomly hangs somewhere in the boot process or even in the BIOS POST). Another interesting thing is that during the POST process the computer always takes unusually long time detecting USB devices (LCD POSTer shows USB INIT), and I've also tried disconnecting all USB devices but didn't take less time to POST BIOS revision is 2702, the latest. Today I found a different behaviour once: during boot screen I got a BSOD with error Stop 0x00000101 A clock interrupt was not received on a secondary processor within the allocated time interval, and this is usually related to overclocking, but I never overclocked my CPU. Judging from the description of my problem, hoping someone had the same and fixed, and since I don't have a spare CPU or motherboard for replacement, I'd like to ask if you think this is a problem with faulty CPU or faulty motherboard, and if I can perform additional tests (I mean software tests because of my lack of spare components) to identify the component to replace.

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• Task Manager always crashes..

  - by tallship

  This is the error report: Problem signature: Problem Event Name: APPCRASH Application Name: taskmgr.exe Application Version: 6.1.7600.16385 Application Timestamp: 4a5bc3ee Fault Module Name: hostv32.dll Fault Module Version: 0.0.0.0 Fault Module Timestamp: 4c5c027d Exception Code: c0000005 Exception Offset: 0000000000068b73 OS Version: 6.1.7600.2.0.0.256.48 Locale ID: 1033 Additional Information 1: bf4f Additional Information 2: bf4f79e8ecbde38b818b2c0e2771a379 Additional Information 3: d246 Additional Information 4: d2464c78aa97e6b203cd0fca121f9a58 Read our privacy statement online: http://go.microsoft.com/fwlink/?linkid=104288&clcid=0x0409 If the online privacy statement is not available, please read our privacy statement offline: C:\Windows\system32\en-US\erofflps.txt Whenever I open the task manager, within a few seconds it crashes, saying it has stopped working with the above report. I took the fault module (hostv32.dll) and scanned it with avast but it found no threat. I also ran a SFC /scannow from an elevated command prompt and it didn't find any corrupted files. This problem is in all two user accounts in this computer (Windows 7). There was one time where task manager seemed to work, but when I closed it and opened it again, it crashed. Any reason/solution to this problem?

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• All browsers crash when file uploading or downloading dialog opens up

  - by Mitulát báti

  I pretty much summarized the problem in the title. I tried to get some solutions. All I found was check if the Chrome has any concurrent or erroneous applications installed on my computer that conflicts with Chrome (by typing chrome://conflicts). But "unfortunately" it said that there are no perceived conflicts. First I thought it is only with Chrome, but soon I saw that no. All internet browsers are affected. I noticed this problem after I installed Fruity Loops, but uninstalling it didn't solve the problem. Maybe Fruity loops is not the guilty reason. Have any of you met this problem before? What should I do? Thank you. UPDATE: Sorry I forgot that this is under Windows 8.1.

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• Website visitors are still being redirected after "fixing" the damage from a conditional redirect website attack

  - by Shannon

  BACKGROUND A website of mine was recently the target of a conditional redirect attack. PHP code was added to my pages to redirect visitors. The .htaccess file was edited to redirect visitors. I've re-uploaded my website so the compromised PHP and .htaccess code have both been removed. My site is mostly handwritten php and static HTML content. I don't use page comments or any third party libraries. THE PROBLEM After removing the compromised php and htaccess files, visitors are still being re-directed. What could be the reason that visitors are still being redirected? Are there any tools to check where/how redirects are taking place so I can debug the problem? UPDATE - PROBLEM FIXED As suggested in the comments, I cleared my Firefox cache and that fixed the problem (for me anyway). Visitors with old cache data will obviously still be re-directed.

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• CPU temperatures high on new build after gaming

  - by Reznor

  My friend had a problem with his computer a while back. His games were crashing, even within the menus. He was stumped as to what the problem was, so I posted on here requesting help. He found out the day later, when his computer would start up but wouldn't display anything on the screen. His video card must have came screwed up. So, he got a replacement. Now, there's a new problem. His temperatures, which were acceptable before, are now insanely high. His GPU temperature runs 70-80c, which is understandable considering he's running his games maxed out, but the real problem here is his processor and motherboard temperatures. All four of his cores are running at 88-90c after coming out of a game. His motherboard temperature was also 70c at one point. In terms of cooling, his case should definitely be adequate. He has an Antec Twelve Hundred. He's using stock fans. The cable management in his case is very good; better than average. He's using the stock heatsink with the processor too, but note, it was fine before the replacement, so it isn't like there's some inherent problem. He has checked the case too. Everything's fine! No cables in the way. The heatsink is seated properly. He turned his case fans up to high, as well, but the temperatures are persisting. Could the processor be overheating due to running games maxed out? Any ideas?

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• System failure - need diagnostic recommendation

  - by Ladislav Mrnka

  I have big problem with my computer. Configuration is: Intel i7 + 6x2GB OCZ DDR3 Motheboard: Asus P6T Deluxe V2, HDD controller configured to AHCI Main drive: OCZ Vertex 2 (SSD) - contains all installed programs and system Second drive: Samsung SpinPoint - contains User profiles, ProgramData, virtual machines and databases Third drive: Samsung SpinPoint - data drive + backups OS: Windows 7 Ultimate x64 I have never had any problem with this computer until now. During weekend my computer completely crashed without any reason. Each time I tried to boot to Windows I got BSOD with message BAD_SYSTEM_CONFIG_INFO and automatic restart (I didn't install any new SW or HW). But after restart main OCZ drive was disconnected (not detected by BIOS). When I turned off and on computer, the drive was again connected. It also happend every single time I tried to repair installation somehow. It ended with some error and after restart drive was disconnected. The only thing which worked was format + fresh install. After installing almost everything I wanted to install Visual Studio 2010 Ultimate (complete installation without SQL Server Express). During installation of VS itself I always get BSOD - it is too fast so I'm not able to read description. After restart it searches for all disk drives for really long time and sometimes it changes boot drive so the system is not able to start - Bootmgr not found. After reconfiguring BIOS the system starts. There is no event describing the failure in Event viewer. Installing VS 2010 is absolutely necessary for me. I need help with diagnostic. I need to find where is the problem - I expect that the problem is in OCZ drive or in HDD controller on motherboard but I don't know how to find it. All components still have valid warranty. Can you recommend me some approach or tools to find the problem? Edit: I'm still looking for source of the problem. New information is that Windows are not able to perform check disk (Chkdsk) on the SSD system drive. After restarting it always starts checking drive and in part where files are checked it fails with BSOD - BAD_SYSTEM_CONFIG_INFO. After next restart and skipping check disk tests the system runs.

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• Why does the mouse always move to the bottom left?

  - by AngryHacker

  In the course of doing stuff on the computer, the mouse always moves, by itself, to the bottom left of the screen - I'd say several times in the course of an hour. I thought this might be an issue with the driver, so I re-installed the driver, but the problem continued. Then thinking that the mouse is faulty, I replaced my Microsoft Wheel Mouse with a Dell mouse. The problem still continues. How can I fix this problem?

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• CentOS Installation on a Cisco MCS 7800

  - by William

  Hello, I'm having some problems installing CentOS 5.5 Final (i386) Onto my server, a Cisco MCS 7800. The problem comes very early into the installation. When the welcome screen comes up ans gives you the option on how to boot into the DVD, Ill press enter to go into the graphical installer. The Screen will then have a blinking cursor in the top left of the screen and will never go away (I thought that it just might need time but I let it sit for over 5 hours.) I then booted into it again and tried using Linux Text thinking it was a problem with graphical installer. That didn't work, same problem. Then I tried a DVD of RHEL 5 and got the same problem, both graphical and Linux text. At this point i think its a hardware problem. The Server has 2GB of ECC RAM, 1 Pentium 4 CPU @ 3.06GHZ and 2 WD Hard Drives (80GB) Configured for RAID 0. ( Also there is a option in the BIOS for what OS type and that is set to Linux.) If anyone has any idea what is going on, it would be helpful. ================Edit================== ooshro, typing "text" doesn't change a thing. still stuck at the blinking cursor. I looked it up and its really the same thing as typing "linux text", which as stated in the first part of my question, i've already done.

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• Windows7 issue in mutli- tasking and memory

  - by Nitesh

  I seeming some problem in my windows OS recently, let me first say my system configuration. processor - Intel(R) Core(TM)2 Quad CPU Q8400 @ 2.66 GHz Installed memory (RAM) - 4.00 GB (3.00 GB usable) System type - 32 bit operating system I am using two OS in this system, first one is Windows7 and the other is centOS. Well, I am using this from a long time there was no problem , and all of a sudden since from couple weeks I am facing problems in my Windows7 OS. In windows7 i was nearing using multiple jobs almost every time i log in, there was no problem but now i don't no what happen I am not able to do multiple jobs at same time. For example- 1 I am now not able to listen to music in windows media player and view photo's. All of a sudden the system stops working and does not respond and then respond after 5mins and the music get played where it got stopped after 5 mins. 2 When i start browersing internet it hangs all of sudden and doesn't respond for 2 or 3 mins and gets loading. I mean it just happens for every operation i do in the system. Even now typing was also difficult, it gets hanged very frequently even though i am doing single task. I have never come across this kind of problem before. So the first thing i did was to see the useage of the processor and the memory. Well, i thick the useage of the processor was fine, for single task the useage was some where around 3 to 5%. Well, it was something weird i found in the memory, in spite of no task that i was running it was using somewhere around 34 to 41% of memory. So i opened the task manager and click on resource monitor in performance tab. And in the memory section of the monitoring tool i found the usage of my RAM, it was something like this. Hardware reserved - 1029 MB In Use - 1430 MB Modified - 49 MB Standby - 1566 MB free - 22 MB And i could also see Available 1588 MB Cached 1615 MB Total 3067 MB Installed 4096 MB well, this if all i could find out and i have no idea why my computer is acting so weird all of a sudden and the performance problem is growing day by day and i also don't know if there is problem in Bios, i have let it for default settings from long time. please help me and Thank you in advance for reading this and helping me.

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• Hosted file is downloaded damaged by IE

  - by victor hugo

  I have a ZIP file hosted via Apache with Akamai as CDN, the problem is when trying to download it with IE (and just IE) it is damaged and I'm unable to open it. Since the problem occurs in other computers in different locations I've discarded network settings (firewall, proxy, etc). I don't even know where start to look? What would be a possible cause for this to happen? UPDATE I'm trying to solve the problem in the server (or CDN), I've verified it's not a client error

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• Windows 7 connect to Lion file sharing

  - by Automaton

  Trying to access my Mac from a Windows 7 computer, I fail with the infamous error 86 incorrect password. Now this appears to be a well-known problem with countless threads on the internet giving as many "solutions" as there are discussion threads about it (mostly ranging from installing third-party commercial samba servers, to switching to some other protocol, to compiling a plain-vanilla Samba installation - the latter which I will probably do when I give up this :) ) I am stubborn, and I believe there must be some problem here that can be solved or worked around, but there is surprisingly little detail about this problem. It appears to have something to do with a mismatch of authentication methods. Trying to run samba in debug mode: sudo /usr/sbin/smbd -debug -stdout gets me this output when trying to access it from Win 7 ... smb1_dispatch_one [smb_dispatch.cpp:377] dispatching SMB_COM_SESSION_SETUP_ANDX smb1_dispatch_session_setup [session_setup.cpp:261] FIXME erase existing sessions log_gss_error [gssapi_mechanism.cpp:97] gssapi: gss-code: Miscellaneous failure (see text) log_gss_error [gssapi_mechanism.cpp:113] gssapi: mech-code: unknown mech-code 22 for mech unknown What is the problem here, and how do I fix it?

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• Task manager always crashes within a few seconds

  - by tallship

  This is the error report: Problem signature: Problem Event Name: APPCRASH Application Name: taskmgr.exe Application Version: 6.1.7600.16385 Application Timestamp: 4a5bc3ee Fault Module Name: hostv32.dll Fault Module Version: 0.0.0.0 Fault Module Timestamp: 4c5c027d Exception Code: c0000005 Exception Offset: 0000000000068b73 OS Version: 6.1.7600.2.0.0.256.48 Locale ID: 1033 Additional Information 1: bf4f Additional Information 2: bf4f79e8ecbde38b818b2c0e2771a379 Additional Information 3: d246 Additional Information 4: d2464c78aa97e6b203cd0fca121f9a58 Read our privacy statement online: http://go.microsoft.com/fwlink/?linkid=104288&clcid=0x0409 If the online privacy statement is not available, please read our privacy statement offline: C:\Windows\system32\en-US\erofflps.txt Whenever I open the task manager, within a few seconds it crashes, saying it has stopped working with the above report. I took the fault module (hostv32.dll) and scanned it with avast but it found no threat. I also ran a SFC /scannow from an elevated command prompt and it didn't find any corrupted files. This problem is in all two user accounts in this computer (Windows 7). Any reason/solution to this problem? Thanks

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• Random and Selective ARP blindness in VMWare ESXi 4.1

  - by Peter Grace

  We have multiple VMWare ESX servers spread out amongst our company, doing various tasks. One particular ESXi host is exhibiting very peculiar behavior. We detect it when our monitoring system (Orion) notifies us that it can no longer ping the box. Upon jumping on the local console of the guest in question, we see that it cannot ping any new addresses that aren't already in its ARP table. At first we thought that the problem was just related to one of our guests, as the problem seemed to always happen to another guest, DevRedis. However, this afternoon the problem swapped and started happening on ApacheBox rather than DevRedis. When I have been fortunate to catch the problem, I have run tcpdump on both sides of the connection (one side being vmware, the other side being a physical webserver) and have noticed the following course of events: Guest ApacheBox sends an ARP request for the physical address of server WindowsBeast WindowsBeast tenders an ARP is-at back to the network indicating its physical mac address. ApacheBox never sees the ARP is-at response. The ESX host in question is running VMware ESXi, 4.1.0, 348481 The two guests (DevRedis and ApacheBox) are both running CentOS 6.3, however they are running two separate kernel versions ( 2.6.32-279.9.1.el6.x86_64 and 2.6.32-279.el6.x86_64 ) so I'm not entirely sure it's a CentOS problem. Does anyone have any thoughts on what might cause this? Has anyone run into it before?

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• Windows fails to restart on reboot

  - by daramarak

  We have many machines running windows xp embedded. The machines are configured to reboot if any problems should occur. But our problem now is that in some cases the machines seems to shut down, but never reboots again. The same machine might reboot fine in the next time we try. Does anyone have clue what the problem might be. Does anyone got some advice on how to debug this problem. Are there any logs that might contain valuable information? Recreating this problem is not done easily so elimination methods are not feasable.

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• Gmail outage only on one computer

  - by user123079

  Problem: Gmail (and only Gmail) quits working for a period of 5-10 mins only on one computer. Problem occurs several times daily Does not appear to be any "triggering event" - user is simply using Gmail normally when the problem arises User can access their Gmail from other computers on same LAN User can access all other sites, including other Google sites, from affected computer After several mins of outage, Gmail will spontaneously resume normal operation on affected computer The problem occurs in all browsers (Chrome, FF, Safari) Computer: MacBook Pro, OSX 10.7.3, latest browsers I find this very baffling. Any advice welcome.

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• Troubleshooting "connection reset" error on my linux server

  - by Chris

  I fervently hope someone here can help me with the problem I am experiencing. I am a programmer, and I have very little understanding of linux sysadmin terminology/concepts. I am attempting to troubleshoot a problem with my website. It is a Facebook app, and whenever I try to connect using Chrome, I get an error stating that the "connection was reset". I have been Googling for four days straight trying to find a solution to this problem, but no joy. A big part of the problem is that I do not understand the terminology being employed, and the output from many of the tools referenced is likewise indecipherable to me. I am running a VPS with CentOS 5, apache, PHP, and MySQL. I could spam this post with a ton of information from my iptables, apache, etc but if anyone needs information from my server, please let me know how to get it, and I will post it here. Thank you for any help you can offer!

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• mouse pointer moving on its own

  - by PA

  After two months of working correctly, I am experiencing an strange and very annoying problem. My mouse pointer is moving on its own. If I move the mouse to the left, as soon as I stop the movement, the pointer runs again to the far right. This makes the mouse totally unusable. The mouse device is an optical USB mouse. It is not a problem with the mouse itself. I have tried with another mouse, same problem. (both mice are OK, I have tried both mice on my laptop, both worked perfectly) Have tried different surfaces, too. Same problem. System is Windows XP Pro SP3. Computer is a desktop PC two months old. I suspected it could be a problem with the mouse driver. But both mice are from different brand, so I suppose they use different drivers. What else can I try? any suggestion?

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• Frequent and weird wifi disconnections

  - by Sidou

  How would you explain, troubleshoot (and solve) the following problem? Wifi ADSL modem router D-link 2640R installed in living room at about 1.8m height. Working fine, synchronising and getting/serving stable internet connection. First situation: -Laptop 01 in other end of the house, let's say in room01 southern to the living room, distant by about 15m. Getting stable signal of good to very good quality. No disconnection. -Laptop 02 in room02 opposite to room01 (5m West) which makes it almost at the same distance and direction from the router located 15m North. Getting stable signal of good to very good quality. No disconnection. Second situation: -Laptop 01 moved to room03 Northern to the living room (actually just 3m behind the wall where the router lies). Getting stable signal of excellent quality. No disconnection. -Laptop 02 still in room02 but now experiences frequent disconnections (actually almost impossible to get the Internet even though the signal level is still very good. Either no Internet with the wifi icon appearing connected to access point or no connection established at all which happens every 2 minutes and that means virtually no Internet at all as I can just get a timeframe of 1 minute or so to load any website or even get to the router's web based control panel. If Laptop 01 is completely shut down or its wifi adapters shut down or even still working but its wifi MAC address forbidden, then Laptop 02 has no problem at all. If Laptop 02 is moved to a nearer location to the router, in the living room for instance, then no connection problem occurs even if Laptop 01 is also connected. And also if we move back Laptop 01 to its original location (room 01), then no problem as well. I'm completely lost and don't know how to address this issue. I tried to change the Wifi channel and even tried the auto channel scan but that didn't solve it. I know that the problem is probably coming from Laptop 01 being in its new location or some sort of interference as the problem occurs only under the described condition but I have no idea how to solve it! I also scanned the neighborhood for wifi jam using InSSIDer, there are few other access points but they don't seem to affect the situation. Any ideas about the steps to follow or tools to use ?

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• Toshiba A205-5804 freezes when plugged in

  - by heron

  Well I have a Toshiba A205-5804 and the problem is that the screen freezes anytime I plug the pc into the external power supply, not as most of the computers having the same issue, my computer DOES freeze in safe mode, and I really can't bear this problem for much longer... It's not an overheating problem, the computer is not getting hot or anything related, I've already tried changing the AC adapter, booting only with AC and no battery, and also all of these suggestions: Try changing the following setting in the bios setup, under the 'Advanced' tab Dynamic CPU Frequency: Mode = Always Low (NOT DYNAMIC) My laptop has been running on AC power without a problem for 24hours, including many restarts, and when I went back to the original bios setting, the problem returned almost straight away. EDIT Other suggestions I found on the web from here and here: Set the power plan to high performance Set the power plan to "Minimal Power Management" (1 and 2 do conflict) Start - Control Panel - Device Manager -- Processor - disable one of two processors - reboot normally 4.Do this: Only plug battery into laptop Turn on the laptop and start Windows normally Plug AC adapter into laptop, the screen will freeze Leave the laptop the way it is for 12-24 hours After 12-24 hours, turn it off the hard way Once it is turned off, turn it back on. The laptop is working now. I have no idea of what can it be...

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• Contacts see me Offline on WLM Althoung I'm online and chatting with them

  - by Eias.N

  Hello, this problem appears just a few days ago , and still till this moment , my problem is that Contacts in my Windows Live Messenger (Version :14.0.8089.726 ) told me that I'm offline while I'm online , some of theme told me that I log in and out every moment while I'm still log in , after that they see me online again , so what is the problem exactly , and how Can i Get rid of it ?

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• How do I prevent TCP connection freezes over an OpenVPN network?

  - by Jason R

  New details added at the end of this question; it's possible that I'm zeroing in on the cause. I have a UDP OpenVPN-based VPN set up in tap mode (I need tap because I need the VPN to pass multicast packets, which doesn't seem to be possible with tun networks) with a handful of clients across the Internet. I've been experiencing frequent TCP connection freezes over the VPN. That is, I will establish a TCP connection (e.g. an SSH connection, but other protocols have similar issues), and at some point during the session, it seems that traffic will cease being transmitted over that TCP session. This seems to be related to points at which large data transfers occur, such as if I execute an ls command in an SSH session, or if I cat a long log file. Some Google searches turn up a number of answers like this previous one on Server Fault, indicating that the likely culprit is an MTU issue: that during periods of high traffic, the VPN is trying to send packets that get dropped somewhere in the pipes between the VPN endpoints. The above-linked answer suggests using the following OpenVPN configuration settings to mitigate the problem: fragment 1400 mssfix This should limit the MTU used on the VPN to 1400 bytes and fix the TCP maximum segment size to prevent the generation of any packets larger than that. This seems to mitigate the problem a bit, but I still frequently see the freezes. I've tried a number of sizes as arguments to the fragment directive: 1200, 1000, 576, all with similar results. I can't think of any strange network topology between the two ends that could trigger such a problem: the VPN server is running on a pfSense machine connected directly to the Internet, and my client is also connected directly to the Internet at another location. One other strange piece of the puzzle: if I run the tracepath utility, then that seems to band-aid the problem. A sample run looks like: [~]$ tracepath -n 192.168.100.91 1: 192.168.100.90 0.039ms pmtu 1500 1: 192.168.100.91 40.823ms reached 1: 192.168.100.91 19.846ms reached Resume: pmtu 1500 hops 1 back 64 The above run is between two clients on the VPN: I initiated the trace from 192.168.100.90 to the destination of 192.168.100.91. Both clients were configured with fragment 1200; mssfix; in an attempt to limit the MTU used on the link. The above results would seem to suggest that tracepath was able to detect a path MTU of 1500 bytes between the two clients. I would assume that it would be somewhat smaller due to the fragmentation settings specified in the OpenVPN configuration. I found that result somewhat strange. Even stranger, however: if I have a TCP connection in the stalled state (e.g. an SSH session with a directory listing that froze in the middle), then executing the tracepath command shown above causes the connection to start up again! I can't figure out any reasonable explanation for why this would be the case, but I feel like this might be pointing toward a solution to ultimately eradicate the problem. Does anyone have any recommendations for other things to try? Edit: I've come back and looked at this a bit further, and have found only more confounding information: I set the OpenVPN connection to fragment at 1400 bytes, as shown above. Then, I connected to the VPN from across the Internet and used Wireshark to look at the UDP packets that were sent to the VPN server while the stall occurred. None were greater than the specified 1400 byte count, so the fragmentation seems to be functioning properly. To verify that even a 1400-byte MTU would be sufficient, I pinged the VPN server using the following (Linux) command: ping <host> -s 1450 -M do This (I believe) sends a 1450-byte packet with fragmentation disabled (I at least verified that it didn't work if I set it to an obviously-too-large value like 1600 bytes). These seem to work just fine; I get replies back from the host with no issue. So, maybe this isn't an MTU issue at all. I'm just confused as to what else it might be! Edit 2: The rabbit hole just keeps getting deeper: I've now isolated the problem a bit more. It seems to be related to the exact OS that the VPN client uses. I have successfully duplicated the problem on at least three Ubuntu machines (versions 12.04 through 13.04). I can reliably duplicate an SSH connection freeze within a minute or so by just cat-ing a large log file. However, if I do the same test using a CentOS 6 machine as a client, then I don't see the problem! I've tested using the exact same OpenVPN client version as I was using on the Ubuntu machines. I can cat log files for hours without seeing the connection freeze. This seems to provide some insight as to the ultimate cause, but I'm just not sure what that insight is. I have examined the traffic over the VPN using Wireshark. I'm not a TCP expert, so I'm not sure what to make of the gory details, but the gist is that at some point, a UDP packet gets dropped due to the limited bandwidth of the Internet link, causing TCP retransmissions inside the VPN tunnel. On the CentOS client, these retransmissions occur properly and things move on happily. At some point with the Ubuntu clients, though, the remote end starts retransmitting the same TCP segment over and over (with the transmit delay increasing between each retransmission). The client sends what looks like a valid TCP ACK to each retransmission, but the remote end still continues to transmit the same TCP segment periodically. This extends ad infinitum and the connection stalls. My question here would be: Does anyone have any recommendations for how to troubleshoot and/or determine the root cause of the TCP issue? It's as if the remote end isn't accepting the ACK messages sent by the VPN client. One common difference between the CentOS node and the various Ubuntu releases is that Ubuntu has a much more recent Linux kernel version (from 3.2 in Ubuntu 12.04 to 3.8 in 13.04). A pointer to some new kernel bug maybe? I'm assuming that if that were so, then I wouldn't be the only one experiencing the problem; I don't think this seems like a particularly exotic setup.

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