Monitor and keyboard powered on randomly?!

[pd2cwe]

My PC was off, not on sleep mode or anything, completely off. All of the sudden, I hear a loud beep and I see my monitor and keyboard powering on. My PC still seems to be off.

Any idea what just happened? I'm scared to touch the PC right now, this hasn't happened before as far as I'm aware.

 

[ninjatuna101]

it sounds like your PC has turn't on. try to wiggle the mouse. Also are the case fans on?