Computer Restarts Randomly - Stops doing it for weeks, does it again

[Vitaliy Vinogradov]

I have had this PC for a while now but ever since I can remember, it has been restarting randomly (usually while I sleep) and then comping back on. When it comes back on it comes back with zero devices detected and unable to find OS to boot to. Then I just restart it a few times and it's back to normal. No rhyme or reason! I have not noticed a patter in why it shuts down, sometimes it will do it constantly, sometimes it won't do it for weeks like now.

I've already tried swapping the HDD's, checking if fans are running, temps etc. I'm still not sure what is wrong. Any ideas? Im assuming it's hardware based.

 

[Ilija Dakic]

Try to remove restart button pins from motherboard, maybe the button is faulty... happened to me :/