Net connection failing after 20-30 minutes of use.

[BrickInTheHead]

After approximately 20-30 minutes of browsing the net / playing a game online, the net fails and I'm forced to use Windows network diagnostic tools to restart the network adapter. Restarting the modem restarts the connection, but again, it dies another 30 minutes or so later.

I've contacted my ISP who say that no issue is going on with the modem on their end, that it's maintaining a proper connection. This is confirmed in that no other computers besides this machine are actually having the issue, so it's clearly something with mine. Occasionally I'll get the error "Cannot connect to the DNS Server 68.xx.xxx.xx" (Where x's are numbers that I can't remember), however this is rare.

Any ideas as to what's going on?

[Shadaez]

Try switching your DNS to googles.