System: Windows 7 Professional 64bit. 8GB RAM, Intel i5-2400 CPU, +300GB free on the hard drive. AVG Internet Security 2012 (enabled & disabled, with firewall enabled and disabled - no effect for either). This computer is less than a year old.

Network: This problem is occurring on a single computer on a network with multiple computers. The router is a Motorola Netopia 3347-02 (DSL Modem/Wireless Router combined). The computer is plugged in directly to the modem, other computers are using the wireless successfully. The router has been reset. The only thing odd about the connection between the router and computer is that it is configured to allow RDP through, so it is assigned a static IP by the router and port forwarding is enabled for port 3389. Also, though I doubt it matters, a second wireless router is active behind this router providing a second network that some computers in the area use without issues.

Details: All downloads initiated on this specific computer eventually fail, this includes streaming from youtube, specialized downloads (itunes), downloads from websites, FTP downloads, etc. Failure occurs with all browsers, but in chrome this is the process it takes: 1) Download begins normally, 2) At some point between (observed) 7MBs and 229MBs the download stops progressing (at this point, if watching chrome's task manager, you can see the network activity for the downloading tab drop to 0kps), 3) for some time the download sits there still attempting to complete, but will eventually display "123,049,871/0 B, Interrupted" (where the number is whatever it actually got to).

The file I am using to test this is a very large .zip file located on a server I control, but the problem seems to occur on any site. The amount downloaded is completely random, and seems to be more time-based than anything (if I start a download immediately after the last one fails, it tends to get further than the last one). Small files can get through for this reason, though they can fail as well. In a test where I simultaneously downloaded the same file via HTTP (chrome) and FTP (windows explorer), both downloads failed at the same instant, though explorer displayed "Connection timed out" several minutes before chrome finally showed the download as interrupted.

Other things I have tried based on advice given to people with similar/identical problems:

• Setting my MTU to 1492 (as described here: http://blog.thecompwiz.com/2011/08/networking-issues.html)
• Disabling write caching to the hard drive
• storing the download on an external device
• successfully transmitted +1GB file from one computer on the same network to this computer
• disabling indexing in the folder the download was being stored in
• disabling all security software
• checked to make sure all drivers were up to date
• read about 50 accounts with nearly exact descriptions of what I'm experiencing, none of which had a solution given

Running Processes:

Image Name                     PID Session Name        Session#    Mem Usage
========================= ======== ================ =========== ============
System Idle Process              0 Services                   0         24 K
System                           4 Services                   0    104,836 K
smss.exe                       332 Services                   0      1,276 K
csrss.exe                      764 Services                   0      5,060 K
wininit.exe                    820 Services                   0      4,748 K
csrss.exe                      844 Console                    1     23,764 K
services.exe                   876 Services                   0     11,856 K
lsass.exe                      892 Services                   0     14,420 K
lsm.exe                        900 Services                   0      7,820 K
winlogon.exe                   944 Console                    1      7,716 K
svchost.exe                    428 Services                   0     12,744 K
svchost.exe                    796 Services                   0     12,240 K
svchost.exe                   1036 Services                   0     22,372 K
svchost.exe                   1084 Services                   0    174,132 K
svchost.exe                   1112 Services                   0     56,144 K
svchost.exe                   1288 Services                   0     18,640 K
svchost.exe                   1404 Services                   0     29,616 K
spoolsv.exe                   1576 Services                   0     25,924 K
svchost.exe                   1616 Services                   0     12,788 K
AppleMobileDeviceService.     1728 Services                   0      9,796 K
avgwdsvc.exe                  1820 Services                   0      8,268 K
mDNSResponder.exe             1844 Services                   0      5,832 K
w3dbsmgr.exe                  1108 Services                   0     43,760 K
QBCFMonitorService.exe        1336 Services                   0     16,408 K
svchost.exe                   2404 Services                   0     28,240 K
taskhost.exe                  3020 Console                    1     12,372 K
dwm.exe                       2280 Console                    1      5,968 K
explorer.exe                  2964 Console                    1    152,476 K
WUDFHost.exe                  3316 Services                   0      6,740 K
svchost.exe                   3408 Services                   0      5,556 K
RAVCpl64.exe                  3684 Console                    1     13,864 K
igfxtray.exe                  3700 Console                    1      7,804 K
hkcmd.exe                     3772 Console                    1      7,868 K
igfxpers.exe                  3788 Console                    1     10,940 K
sidebar.exe                   3836 Console                    1     84,400 K
chrome.exe                    3964 Console                    1     19,640 K
pptd40nt.exe                  4068 Console                    1      5,156 K
acrotray.exe                  3908 Console                    1     14,676 K
avgtray.exe                   3872 Console                    1      9,508 K
jusched.exe                   4076 Console                    1      4,412 K
iTunesHelper.exe              1532 Console                    1     87,308 K
SearchIndexer.exe             3492 Services                   0     36,948 K
iPodService.exe               4136 Services                   0      7,944 K
BrccMCtl.exe                  4276 Console                    1     18,132 K
splwow64.exe                  4380 Console                    1     32,600 K
qbupdate.exe                  4836 Console                    1     24,236 K
svchost.exe                   4288 Services                   0     20,700 K
wmpnetwk.exe                  3112 Services                   0      9,516 K
FNPLicensingService.exe       5248 Services                   0      5,852 K
QBW32.EXE                     5508 Console                    1    127,068 K
QBDBMgrN.exe                  5600 Services                   0     42,252 K
EXCEL.EXE                     2512 Console                    1     99,100 K
LMS.exe                       3188 Services                   0      5,616 K
UNS.exe                       1600 Services                   0      7,308 K
axlbridge.exe                 5260 Console                    1      5,132 K
chrome.exe                    5888 Console                    1    200,336 K
chrome.exe                    3536 Console                    1     26,076 K
chrome.exe                    1952 Console                    1     20,168 K
chrome.exe                    4596 Console                    1     24,696 K
chrome.exe                    4292 Console                    1     48,096 K
chrome.exe                    2796 Console                    1     23,520 K
Acrobat.exe                   1240 Console                    1     87,252 K
123w.exe                      4892 Console                    1     22,728 K
calc.exe                      1700 Console                    1     12,636 K
chrome.exe                    1328 Console                    1     28,888 K
chrome.exe                    3696 Console                    1     47,012 K
rundll32.exe                  6320 Console                    1      7,104 K
chrome.exe                    4928 Console                    1     44,248 K
AVGIDSAgent.exe                260 Services                   0     12,940 K
avgfws.exe                    6052 Services                   0     26,912 K
avgnsa.exe                    5064 Services                   0      2,496 K
avgrsa.exe                    3088 Services                   0      2,200 K
avgcsrva.exe                  2596 Services                   0        380 K
avgcsrva.exe                  6948 Services                   0        408 K
StikyNot.exe                   452 Console                    1     14,772 K
chrome.exe                    4580 Console                    1     28,200 K
chrome.exe                    4016 Console                    1     57,756 K
svchost.exe                   7140 Services                   0      4,500 K
chrome.exe                    6264 Console                    1     56,824 K
chrome.exe                    7008 Console                    1     56,896 K
chrome.exe                    2224 Console                    1     38,032 K
taskhost.exe                   612 Console                    1      7,228 K
chrome.exe                    6000 Console                    1     10,928 K
chrome.exe                    2568 Console                    1     43,052 K
chrome.exe                     272 Console                    1     75,988 K
chrome.exe                    7328 Console                    1     53,240 K
PaprPort.exe                  7976 Console                    1    137,152 K
pplinks.exe                   7500 Console                    1     14,052 K
ppscanmg.exe                  5744 Console                    1     18,996 K
taskeng.exe                   7388 Console                    1      6,308 K
SearchProtocolHost.exe        8024 Services                   0      8,804 K
SearchFilterHost.exe          7232 Services                   0      7,848 K
chrome.exe                    8016 Console                    1     37,440 K
cmd.exe                       7692 Console                    1      3,096 K
conhost.exe                   7516 Console                    1      5,872 K
tasklist.exe                  8160 Console                    1      5,772 K
WmiPrvSE.exe                  7684 Services                   0      6,400 K

Any help with this would be greatly appreciated, I've been beating my head against a wall over this all day. This computer serves dual purpose as the main company document server and the Owner's work computer, it's fairly important it be fully functional and I cannot figure this out.