losing internet connection

I've been running Vista 5384 with no Internetproblems whatsoever sinds it came out, but since yesterday my internetconnection stops working after a couple of hours (I think). Very annoying.
I'm running it on a P4 2.8 GHz, 2 GB RAM, Nvidia Geforce 6800 GE, onboard Ethernetcontroller (3COM).
I have no idea what it could be, but maybe someone has had the same problem and is now thinking "Hey, I know what that was :-) "

I've been running Vista 5384 with no Internetproblems whatsoever sinds it came out, but since yesterday my internetconnection stops working after a couple of hours (I think). Very annoying.
I'm running it on a P4 2.8 GHz, 2 GB RAM, Nvidia Geforce 6800 GE, onboard Ethernetcontroller (3COM).
I have no idea what it could be, but maybe someone has had the same problem and is now thinking "Hey, I know what that was :-) "