Game freezes and shuts down computer

[Max Power]

I've got a problem with Cryostasis. The game is running just fine when I boot it up, but after 3-5 minutes the whole game freezes. And not just the game, it freezes the whole computer as well. I can't do anything. It stays that way for about thirty seconds and then a bluescreen flashes by for a second before the computer shuts down.

I've tried to update the drivers for my graphics card but it doesn't help.

I'm running it in Windows XP on a Intel Core Duo CPU, E4500 @ 2.20 GHz x2 with 2 GB RAM.

My graphics card is a nVidia GeForce 9600 GT.

As I said, the game runs just fine until it freezes up and shuts down my computer. Help would be greatly appreciated. I'm starting to get desperate here.

Oh yeah, one more thing. I bought the game through Steam. Don't know if it has any significance but I thought I'd mention it just in case.