What is making my game freeze until restart?

[jonajohnson3]

The computer I use is really really really old, my parents made if for me.
I should be building a new one soon but I would like to know why my game (team fortress 2) freezes until i restart my game.

Specs (Not a master it was from a steam survey)
https://shrib.com/#XD79XriCCqJ0.H10cv_-

From what I can see through the little holes on the side, its coated in a cm of dust.

 

[jonajohnson3]

+note Right before it freezes it will sometimes show discoloration and dupes of the background. Another note it plays back the sound over and over and over and ect.