Vista - Problems running any game on Vista Business x64

Hello there,

Any game I run on Vista Business x64 gives me some problems. I can play
games for anywhere between 4 minutes and 4 hours. But after a certain amount
of time, my computer completly locks up (not even a BSOD). The game just
freezes and my sound goes berzerk (it's sounds like a weird repeating sound
kind of virus like). I have run all virus scans, disk defrag and updated all
of my drivers. I had SP1 installed and thought that it might be the problem.
I uninstalled SP1 but it happened again.

I am now at a standstill and do not know what else needs to be done...

Any help would be appreciated.

Thank you,

Varant