Computer shuts down after some minutes

[plutomaniac]

Of course it depends from game to game and from program to program. In theory, your computer can shut down even if you watch a 1080p youtube video. Unless there is gpu hardware acceleration, cpu resources will be used raising the temperature above 100°C and then shuting down to prevent damage. Also it is true that as heat rises your cpu will be slower.

And yes, cleaning out dust is the first thing to do but I think you said you did that. In case your aftermarket cooler is indeed very weak, try the stock intel one. That change will also force you to change the thermal compound and resit the heatsink which I believe will fix the overheating problems.

EDIT: Or format your PC completely.

It's a hardware problem. That would be a waste of time. It won't solve the issue.