Everytime i start up the game they start great but eventually end up freezing the pc or bsod(blue screen of death) here are my system specs: Windows 7 home premium 64-bit(6.1,build 7600) AMD Phenom(tm) II X3 720 Processor (3 CPUs), ~2.8GHz 2048MB ram NVIDIA Geforce GTX 260
I'd suppose that you have too old drivers. You should give a try and update them. And if you haven't paid for the game, that's the problem.
I had the same problem with the blue screen of death. I turned out (in my case) that the video settings in the game were not in the correct number. My resolution was too low so i maxed it out and it worked. For you, i would suggest re-installing, and update every possible driver. take a look this this website for help; helped me a lot. http://www.mapmodnews.com/article.php?story=Call-of-Duty-Modern-Warfare-2-Errors
it was my video card...it was messed up..well at least i think...i sent it back to the company and they are gonna send me a new one