Computer lags , freezes , then an black screen appears

[aLexFTW]

Ok , so I have been having this problem since the last summer ... Basically I turn on the game (any game) and it works just fine . Ok? For 5-7 minutes it works ok ! But then ... well.. it lags , it freezes and then the screen turns black , what's interesting about it is that right after the screen turns black and display the message 'd-sub no signal' is that an error sound pops-up...
Please help , I tried to solve it from last summer , everyone said it was a psu problem , so , i bought a new one ... but no .. it is not the psu ...

 

[aLexFTW]

one more thing

Oh yeah , and also , when the pc used to work it heated up really bad , almost like it was going to explode .. But now it's cold AF whatever i do..
(Sorry for double post)

 

[dominickbuff]

Ok I have a few questions for u 1. Is your cpu cooler dirty? Is your intake fan dirty? If your gpu fan dirty? And what's your gpu temp while gaming?