It's a shock to people that most problems are to do with hardware troubleshooting - but if your PC isn't really possible to troubleshoot, by all accounts other than fiddling with your operating system the hardware itself can be replaced with a brand new PC. And besides, people buy computers for a specific purpose, which, if it is gaming, is only half of why everyone buys a computer in the first place.
If it's Windows 7, it may be the cause of the problem is to do with the cause of the overheating, and overheating is based on many variables - including the speed at which the computer is working, the quality of the fan, and the quality of the fluid in the cooling system. If you have the most famous overclockers in the world, then they are still susceptible to various scary major explosions if your computer doesn't run at the required clock speed, which can cause your machine to overheat.
If you are thinking about buying a high-end gaming computer, it would probably be a good idea if you install a replacement cooling fan, but it might just be that there is a problem with your laptop's cooling system.
It's also a possibility that your graphics card may be incompatible with Windows 7 - but if computer runs perfectly in OS X it's unlikely that the problem is software - the graphics card itself. d2c66b5586