Has the computer been on the internet before (I mean through that connection, did it just suddenly not work?)
What OS is installed?
Is your ethernet on-board or a PCI card?
If on-board, then what is your motherboard?
If PCI card, then look on the card for the manufactor (download drivers from site)?
Is this the first time you used the card? in that computer?
If you just put the card in, try switching it's PCI slot to a different one.
If you can answer some of those, then I can help 
|