Tirdnfrustrated

Hi everyone, I stumbled across this forum accidentally via google and since you all seem a helpful bunch I was hoping you could help me, it would be greatly appreciated.

A few days ago I bought a new computer (system specs should be in my profile for reference) with vista ultimate 64 bit installed. It's working beautifully so far except for one major problem, it freezes constantly! Whenever I open up a game I can play for about 10 minutes to half an hour (sometimes less) and then the whole thing will just freeze. At one point it even happened while I was compressing a new .rar archive. I've tried everything I can to fix the problem, updating and installing and reinstalling drivers many times over, updated vista, reinstalled vista on a clean install, tried with nothing but updated nvidia drivers and I still get it.

Right now after the format I'm on a fully updated sp1 system and of course it's still happening. I'm at my wits end here and nothing I try will make it go away. This basically makes my computer unusable for my needs as I'm primarily a gamer. I really don't want to go back to xp, as I love Vista but I'm gloomily facing that outcome if I can't find any way to get it working properly.

Thanks in advance for the help!