Strange Occurence: Computer tried to turn on by itself?

[necrogaming]

Hi guys. So this just freaked me out. It's about right around 3AM this happened and according to movies that's when the spirits start acting up or so they say. Anyway, my computer was completely shut off when suddenly it started flickering. I could hear the audio jack, like the sound it makes when you connect it and there's a little static sound? Yeah that. The fans started spinning for a bit dying and repeating. I had the LED lights connected to my psu as well so that flickered too which btw intensified my fears. I didn't know what to do so I unplugged the psu. Any theories on what caused this? I wasn't even sure what forum to put this under. Btw i just recently installed a new gpu into the mobo could this be part of the problem? Or the mobo itself?

 

[Jasjar]

http://www.tomshardware.com/forum/361394-31-computer-turns-randomly