Endless Paradigm

Basically I has exactly the same problem the other day. Then I went to the motherboard's website and downloaded ethernet drivers...

yeah the drivers on cd are probably the initial release, go to nvidia web page and get latest chipset drivers, then mobo web page and get latest network drivers (but those should get installed with nvidia chipset if its nvidia network card)

Is this a new router?  Power off your cable modem and router, let sit for a few minutes, then power on cable modem, then power on router.

Also maybe you can repair your network adapter with windows?