My computer is possessed

I don’t know if I’m telepathic, or if my computer’s possessed; it just turned itself off (suddenly; it didn’t go through the shutdown process(Although some stuff I was listening to hung for about a second after the monitor turned off)), so I attempted to open it to see if the cord on the GFX card had been pushed out (that happened once before, and it did the same) but before I could get the second screw off, it started up again. Doubtful as to whether I had pushed the power switch or not, I turned it off while it was booting (bad, I know, but it’s never done anything before) but this time I couldn’t even get behind the computer before it turned itself on again, and this time I know I didn’t press anything.

Anyone know anything about this kind of stuff?