Computer turns off and when I try to restart no monitor monitor signal

[larsa]

So usually when I'm playing games. My computer will completely shut down and then when I try to turn it back on it'll turn on but the monitor wont get any signal and it doesn't seem to actually boot just turn on the keyboard and mouse don't seem to get any power either. it'll only work after not using it for a little bit and work just fine I've tried watching the temps of my cpu and gpu while playing games cpu was 45c and gpu 59c on average. So I really don't know what it is any ideas? Also i have tried using another gpu when it does this and still wouldnt work till i left it for awhile

 

[Old Guy Geek]

Well, since the symptoms are classic overheating, and it sounds like you've eliminated the GPU, it must be your CPU. But depending on the newness of your CPU, it should just throttle back to prevent overheating. In extreme cases it would shut down.

Because your mouse and keyboard aren't coming on right away, it could be a PSU problem. It could be failing under high load, dropping voltages until the system fails. Maybe a good air cleaning of your computer's interior and the PSU vents is in order?

 

[Tim Locke]

I agree. Vacuum all the vents and if your cpu has the usual cooler with the fan on top of a heat exchange radiator pay attention to that carefully. You may find it full of dust. I would pick it out carefully with a toothpick and then vacuum it. Dont remove the fan as you don't want to disturb the radiator's contact with the cpu.

You might also check the wattage of your PSU and how much power the Graphics card can take under load. As OGG says it could well be the PSU...they are cheap to replace if there is any doubt.