Computer crashing when gaming

[wattheheal]

Hey guys had my comp for a while but fore some reason it has been crashing when i game. TO specify I can play games for anywhere between 15-45 minutes and then the screen will blink a few time and computer will crash (if I alt f4 the game quickly the computer will work fine afterwards), sometimes it doesn't blink at all it just crashes. This occurred with CS:GO, League of Legends, Diablo 3. Seems to have started with windows 10 update.
I have updated all drivers, un-installed AMD catalyst control centre, cleaned the computer, checked the temps.

Comp Specs
MOBO: MSI X58 Pro-E
CPU: Intel Core i7-960
GPU: ATI Radeon HD 5770
Memory: 6Gig DDR3 kingston
HDD: Hitachi HDS721010CLA332 1TB

Any help is greatly appreciated.

 

[Vic 40]

Are you able to try with a different gpu? Maybe from a friend or ...
Which psu? Make/model/wattage.
Tried with windows energy settings at high performance?