Only a heating problem? If your PC is overheating then it's a serious problem, as heat can rapidly damage your hardware. Causes of overheating are many, ranging from broken fans, underpowered Power supply, blocked vents, excessive dust, underpowered computer for the process (game), etc. It's not good to use a PC in situations where the graphics chip overheats to the point of failing. You should fix the problem, or get higher powered hardware, whichever is applicable.
It actually was only a heating problem. I was just playing too long and I was playing it on my lap (using my laptop)!! I know that was stupid. Good thing I got the blurry screen before it melted my motherboard. Now I play a while then rest and ONLY play on a solid surface. I haven't had any problems since. But it could also be another problem, so make sure you check Simsample's suggestions.