Very strange one, not sure whether it's in the right category here as I may not be a Windows 10 problem, it may just be my PC.
Had it a couple of years, its a gaming one so it MAY just be getting old.
I'm sitting here and it just turns off randomly, the weird thing is, as soon as it turns off I press the power button and it comes back on straight away. Surely that doesn't mean its overheating? If it was overheating then surely it wouldn't come back literally straight away? I've actually opened the PC up and cleared the dust etc and ive left the cover off it so air can get to it.
You probably need more info, ive done this on my phone so apologies about grammar etc