System Crashes and Performance Problems

[darcyg]

I recently just purchased a new game (Mass Effect) and I'm having an issue running it. It runs fine for about a minute or two but after that my whole system will shut down out of no where.
I've been trying to figure out if it's a system problem or a game problem, when I started to play a very old game that should run perfectly( and always has) on my system. I noticed that after about the same amount of time passed the game began to run very slowly.
I think it may be an overheating problem. The bottom of the laptop tends to get very warm, but I'm not sure I can equate this with the performance/crashing problems.
Some Basic Info:
Intel Core 2 Duo 2.2 GHz
3.070BG ram
nVidia GeForce 8600m GT 512mb
What I'd like to know is should I perhaps change my cooling system? and if so what to? here is my system: http://vigorgaming.com/product/rigs-ares.html
Or does this look like it may be caused by something else?

Thanks!