Asus G73JH Shutdown Problem

I have been having this problem with my computer recently where it just shuts off a few minutes (sometimes seconds) after i start playing a game, i always thought it was just a heating issue, but i have recorded the temperature during game play and it never exceed 80.C .

So i'm not sure whats wrong but i did notice that my GPU jumps from 0% to 100% then drops back down to 0% and shuts off, but i honestly don't know.

and if y'all want me to record whats happening feel free to ask.

Asus G73JH Shutdown Problem