Hey wassup,
I have the same problem... i am running under win2k, i have a p4p800-vm motherboard, i am connected to a lan and then to the internet. It has always worked fine with my old system and now it does not work.
More precisely it does not go on the internet except than google and some random website that i have tried just opening a million windows just to check.
Again i see all the computer on the network, emule works fine but not the internet.

I have encountered this problem before with win2k and xp but there was a simple chenge to make which was setting the MTU value in the windows registry. Same thing with win98 but in another way. BUT even doing this on the new system nothing changes. Just freaking google.
I know for a fact that the IP and DNS values are right (i wold not be able to see the lan nor connect with emule)... I am really starting to think that the motherboard lan controller has issues, and it looks like i am not the only one having this problem, wheter a linux or win user.
Tell me what you guys think about...thank you for your attention

goodbye