There's possiblity that it could be BSOD, If you tweaked your pc to automatically restart if BSOD appears - for short you might disabled BSOD show up.
Or your pc is too hot?
So , Is it possible to reformat your 'C' Drive using 'D' Drive? .. I dont have USB , CD & DVD atm .. I was wondering if I could do this? .. Is it bad? -