Hi and welcome to TechIMO.
When does it happen? While you're playing PC games, is it?
Well, you could try to use the main board graphic first, to see if it is your graphic card problem. If it is the cause, then somethings wrong with it.
It seems to me that something is so highly unstable in your system. Do you remember anything at all what was your last installed programs on the day that you think it started to happen so awkwardly?
What I would do is, I would reinstall Windows or repair it.