From all my searching, this appears to be a common issue. That said, I haven't found a solution that works thus far.
I have two computers (PC1 and PC2), both with Win XP Pro SP2 connected to each other and the internet via my Netgear DG834 ADSL Modem Router. Both were working fine, then all of a sudden, PC1 started saying "A network cable is unplugged". Nothing new had been installed on the system.
* Windows updates ARE set to automatic. Problem first noticed: Sunday, March 9, 2008.
* Computer ventilation holes were blocked by a lot of dust.
Error resolution attempts thus far:
* Checked CAT5 to make sure cable was plugged in OK. It was.
* Tried switching cable from PC1 to PC2. Connection worked fine. Therefore, it's not the cable and it's not the port on the router.
* Cleaned out as much dust as I could find from PC1. No luck.
* Bought a new network card (NETGEAR FA311 v2 PCI) and installed that. No luck.
* Tried running "WinsockxpFix.exe" from http://www.watchingthenet.com/repair-windows-xp-tcp-network-settings-with-winsock-xp-fix-utility.html. No luck.
If anyone can point me in the direction of any possible solutions that would be VERY much appreciated!!!