I hope this can still help you:
Go to Device Manager/Device Drivers
Disable microsoft UAA bus driver ...
Uninstall UAA bus driver
Install realtek driver and it will work.
I just joined this forum and I am a bit late with this but this will work.
Well,my friend... I would like to say that i have same problem! bealive it or not!!! I have windows xp sp2, and my motherboard is gigabayte Ga-m68SM-S2 nForce 630A/GeForce7025. I`we tried everything!! Probably,almost everything!! Nothing works.... Problem is always the same... i read carefullyevery your comment and try to solve the problem the way you said! Still, nothing works... HELP!!!