I see you're always prepared for the worst. That's good!

Perhaps faulty PSU? I had one that started up at completely random times, I looked through the BIOS and all the power on settings were off, I just couldn't understand it.

Then when i upgraded video card I replaced the psu with a bigger one and the problem is now gone.

Trojan...


































































Jk

It's the Google Analytics! they've gone from tracking you to stuffing so many Googles in to your system that it's not alive! RUN! FLEE THE HOUSE!

Unless the PC was manufactured by the Cyberdyne Systems, I think you don't have to worry about it :-D

I was going to suggest mischievous vermin were at fault. I had a mouse turn my laptop on once when I was at a camp, which was pretty impressive.

But your computer turning on without a power source? That's even MORE impressive.