Network is not working anymore - Ubuntu 12.04

Hello, I have a problem with my network connection. I have been using the same laptop with Ubuntu and the same connection for more than a year, and suddenly yesterday the connection stopped working (both wireless and wired). I've tested with another computer and the connection is fine (both wireless and wired).

I've been reading similar posts but I haven't found a solution yet. I tried a few commands that I'm posting here (my system is in spanish, so I have traslated it to english, maybe the terms are not accurate):

grep -i eth /var/log/syslog | tail Jun 3 18:45:40 vanesa-pc NetworkManager[3584]: (eth0): now managed Jun 3 18:45:40 vanesa-pc NetworkManager[3584]: (eth0): device state change: unmanaged -> unavailable (reason 'managed') [10 20 2] Jun 3 18:45:40 vanesa-pc NetworkManager[3584]: (eth0): bringing up device. Jun 3 18:45:40 vanesa-pc NetworkManager[3584]: (eth0): preparing device. Jun 3 18:45:40 vanesa-pc kernel: [ 7351.845743] forcedeth 0000:00:0a.0: irq 41 for MSI/MSI-X Jun 3 18:45:40 vanesa-pc kernel: [ 7351.845984] forcedeth 0000:00:0a.0: eth0: no link during initialization Jun 3 18:45:40 vanesa-pc kernel: [ 7351.847103] ADDRCONF(NETDEV_UP): eth0: link is not ready Jun 3 18:45:40 vanesa-pc NetworkManager[3584]: (eth0): deactivating device (reason 'managed') [2] Jun 3 18:45:40 vanesa-pc NetworkManager[3584]: Added default wired connection 'Wired connection 1' for /sys/devices/pci0000:00/0000:00:0a.0/net/eth0 Jun 3 18:45:40 vanesa-pc kernel: [ 7351.848817] ADDRCONF(NETDEV_UP): eth0: link is not ready

ifconfig -a eth0 Link encap:Ethernet addressHW 00:1b:24:fc:a8:d1
ACTIVE BROADCAST MULTICAST MTU:1500 Metric:1 Packages RX:0 errors:16 lost:0 overruns:0 frame:16 Packages TX:123 errors:0 lost:0 overruns:0 carrier:0 colissions:0 length.tailTX:1000 Bytes RX:0 (0.0 B) TX bytes:26335 (26.3 KB) Interruption:41 Base address: 0x2000

lo Link encap:Local loop
Inet address:127.0.0.1 Mask:255.0.0.0 Inet6 address: ::1/128 Scope:Host ACTIVE LOOP WORKING MTU:16436 Metrics:1 Packages RX:1550 errors:0 lost:0 overruns:0 frame:0 Packages TX:1550 errors:0 lost:0 overruns:0 carrier:0 colissions:0 long.tailTX:0 Bytes RX:125312 (125.3 KB) TX bytes:125312 (125.3 KB)

iwconfig lo no wireless extensions.

eth0 no wireless extensions.

sudo lshw -C network *-network
description: Ethernet interface product: MCP67 Ethernet manufacturer: NVIDIA Corporation Physical id: a bus information: pci@0000:00:0a.0 logical name: eth0 version: a2 series: 00:1b:24:fc:a8:d1 capacity: 100Mbit/s width: 32 bits clock: 66MHz capacities: pm msi ht bus_master cap_list ethernet physical mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation configuration: autonegotiation=on broadcast=yes driver=forcedeth driverversion=0.64 latency=0 link=no maxlatency=20 mingnt=1 multicast=yes port=MII resources: irq:41 memoria:f6288000-f6288fff ioport:30f8(size=8) memoria:f6289c00-f6289cff memoria:f6289800-f628980f

lsmod Module Size Used by usbhid 41906 0 hid 77367 1 usbhid rfcomm 38139 0 parport_pc 32114 0 ppdev 12849 0 bnep 17830 2 bluetooth 158438 10 rfcomm,bnep binfmt_misc 17292 1 joydev 17393 0 hp_wmi 13652 0 sparse_keymap 13658 1 hp_wmi nouveau 708198 3 ttm 65344 1 nouveau drm_kms_helper 45466 1 nouveau drm 197692 5 nouveau,ttm,drm_kms_helper i2c_algo_bit 13199 1 nouveau psmouse 87213 0 mxm_wmi 12859 1 nouveau serio_raw 13027 0 k8temp 12905 0 i2c_nforce2 12906 0 wmi 18744 2 hp_wmi,mxm_wmi video 19068 1 nouveau mac_hid 13077 0 lp 17455 0 parport 40930 3 parport_pc,ppdev,lp forcedeth 58096 0

Let me know if I can give you more information. Thank you very much in advance, Jonathan