Ethernet "Cable Unplugged" when it's not

I'm using Kubuntu 10.10, and Network Management is saying that both of my ethernet cards are unplugged. While that is correct for eth0, eth1 should be working (it works in Windows, and used to work here until I installed a lot of updates recently).

I'm using wifi at the moment, which is working fine, but I'd prefer to use a wired connection.

I am reasonably proficient with linux, I've been using it for several years for work, and I'm perfectly happy to use the console and edit config files. I don't know the specifics of networking, though, so I don't know what information would help with diagnosis of the problem.

Any idea?

Please help.

Thanks!

I didn't find the right solution from the Internet.

References
ubuntuforums.org/showthread.php?t=1709957

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