Intermittent "network cable unplugged"

[MTColl28734]

I've checked a bunch of posts about this subject, but all of 'em seem to involve a router and multiple computers. I have a friend who has two computers connected to a DSL modem. One of them has no problem staying connected, but the other keeps flashing the unplugged message every 2 or 3seconds. I can actually watch the tray icon alternate between "acquiring network address" to "network cable unplugged". Same thing in Network Connections. I can also watch the modem's light for the port being used go from flashing to off and back again.

I turned off the power management on the NIC, installed a PCI LAN card, changed the cable, changed the port on the modem, reinstalled the drivers for both LAN ports, disabled each of the LAN ports in turn, ran Winsockfix, ran IObit Advanced Care System, & ran system file checker.

He has AVG installed, but I've never had a problem with it blocking a connection, so I doubt that's a problem.

It's got me beat, folks! Short of doing an XP repair, what's left?

[johnwill]

Try booting in Safe Mode with Networking and see if it still behaves the same way.

[MTColl28734]

One thing I forgot to mention is that when I bring the computer to my shop, it works fine. That would, I'm sure, indicate that the DSL modem is to blame, but as I mentioned, the other computer hooked up to it works just peachy.

HMMMMMMMMMMMMMM................

[johnwill]

What is the exact make/model of the router? Is the office connection a wired connection also?

Consider sticking a cheap Ethernet switch between the router and the computer in question, this is starting to sound like some sort of electrical or grounding issue.