|don't buy the game again, that almost certainly won't resolve your issue.|
can you play other games for long periods of time without the software crashing?
have you stress-tested the CPU and RAM with Prime95? That could tell you if your system hardware is going bad.
it sounds like the application is crashing, but not the whole PC. You might be able to look at the Application Log in the Event Viewer to get a better idea of what is going on.
updated graphics drivers might address your issue. Or a repair/reinstall of the game.