Crysis Shutting Down my new Gaming Rig

I just put together my first PC. Relatively new to it all, but it seemed to go well. Took me a while to figure out how to work SLI and all but once I figured it out I installed WoW and put it at max settings and it worked awesome. Next I installed Crysis, it starts fine, plays beautifully then it gets to the first cut scene, where they find dead bodies, my computer shuts off...then restarts itself. If anyone has any idea on what I may have installed or done wrong, please let me know...thank you. Here are my specs:

Thermaltake Black Kandalf LCS Full-Tower
EVGA X58 Classified Motherboard
Dual EVGA nVidia GTX 275 1792MB
Core i7 950
12G Corsair Core i7 Dominator PC12800 DDR3 RAM Tri-channel
2 Seagate Barracuda 7200 - 750GB
Kingwin Mach 1 Modular Power Supply - 1220w


I do not have the Liquid cooling ste up yet...I am waiting for a water block that fits my Core i7, but I do have cooling cases for my HD's, Fans for my RAM and on the CPU I have the Thermaltake SpinQ CPU Coooler.

Again thanks for any information you can give me...and if you need any more info on my system...let me know.

No I have not...I will look into DLing them and run them...thanks!

Obsidian, thanks for your help. I ran those tests and all came back fine. So I did some tinkering and what is happening is my graphics cards are overheating. Took off the side of the case and it works, until I crank up the settings to the highest grphical setting then it crashes again. Basically I need more fans. But thanks again for helping me pipnpoint the issue.