Welcome to the forum
*gazes into crystal ball*
Tidy your room, that should help.
If that doesn't fix it, please supply more info. I have the best crystal ball here, yet your situation is quite cloudy. Suggestions here:
If you're looking for advice, the best way to get it is by providing as much information as possible right from the start. This allows other readers the context they need to point you in the right direction. Here are some suggestions to improve your chances of getting solid answers: What should...
forums.pcgamer.com
Of particular interest are:
Exact make & model of your Power Supply;
Motherboard;
Case & cooling parts;
Graphics card;
Monitor model & Hz;
Resolution you're running at;
What graphic settings level have you enabled?
Are all drivers & BIOS up to date?
Have you tried the simple step of uninstalling and reinstalling the game?