Computer Crashes when I launch games

Hi everybody, I haven’t always had this problem with my computer, it only began to happen a few months ago.

I really enjoyed playing games on my rig but since this problem began its become more of a stress filled roller coaster as to whether I join a game successfully, or my entire system dies.

It occurs no matter the game, most of the time only after the game has been running for a short while.

I mostly play LoL, and it only ever crashes just as you load into the game.

The system flashes to a black screen suddenly, then produces a random color onto my screen and it stays in this position until I force reset my PC. I can still hear audio from the game but I cannot input anything either (eg abilities, ect).

I’ve updated all of my drivers, installed new fans to prevent overheating, and cleaned the entire thing of dust very carefully.

If somebody could please help me out that’d be a huge help, thanks everybody!!