Computer crashing from unknown source

I recently upgraded to windows 7 with reformat and all meaning a clean start with no documents or anything. After buying 2 gigabytes of ram (making my 1 gig now 3 gigs) and buying a "Nvidia 9800 GT 512mb" video card I was set to go. I loaded up World of Warcraft and was able to play for around 2 weeks. After a while my computer would lock up meaning i would have to force restart by pressing the restart button on my computer. This continues to happen repeatedly but only when I play graphical games such as World of Warcraft or heck even Audiosurf freezes. I have read many posts about it being due to the Nvidia 9800 GT drivers conflicting with Windows 7 while my friend says my outdated single core 2.00 Ghz processor is to blame. I don't want to go buy a new processor and motherboard only to have it continue to hard freeze on me any help?

**Edit** - I have run both memory tests and hardrive tests and both are clean
**Edit** - Z0mg someone please help me no one knows my problem it is like one in one trillion chance

Welcome!

Although your processor is on the lower powered side, I doubt it's the issue. Nothing changed, except for RAM and GFX card.

Try installing the latest drivers from below:

[nvidia][/nvidia]

Try uninstalling your GFX card drivers, and installing an older version.

I suggest returning or RMAing the video card.