Really if you are not overclocking anything and have a case fan or two, nothing should be overheating.... Are you using a a case with everything cramped together? Try running a CPU burn in and see if that causes your computer to reset. Memtest 86 will tell you if the ram is the problem. Otherwise it is likely your GPU with the problem. I have a passively cooled 7600GT, and it seems to work for over 3 week stretches without complaint. I always leave my computer on, and have never had any problems with overheating as of yet. Anywho, the quick and dirty way to solve your problem is to take of the side panel and put a box fan next to it If that dose not work and it is certainly your GPU that is the problem, it is likely a manufacturing fault, get your money back and buy an actively cooled version.