On-board LAN on AI7 doesn't work

I bought an AI7 last saturday. Its on-board LAN didn't work. So I took it back and replaced for a new one today. But the new one doesn't work also. Now, I'm thinking maybe it's my mistake.
I've already enabled the on-board LAN in bios and I can see it in windows My Network Places' Properties. But when I plug in the LAN cable, there is no network. I tried to plug the LAN cable into my old network card in AI7, it works fine.
So... is there anything you guys can think of but I didn't do?

You have to install the drivers from the Abit install CD.

Wow we have a very similar setup. Anyways, use the abit cd and install the drivers for it. Mine stopped working to, but after i reinstalled the drivers it started working

I installed it's driver from the CD already but it still doesn't work. I'm using my old network card anyway.