Ok so, I was playing Hearthstone and all of a sudden my pc shut off. And I don't mean shut off instantly, a few of my apps shut down, then everything closed 1 by 1, i tried clicking the start button to close it, but it kept practically closing(like if i hit the start button then click to somewhere else and it goes away). This can't be hardware, got a brand new PSU recently and everything was fine.(using Win7). Then it booted itself up again but I force shut it down. I mean, it wouldve been somehow fine if it just shut down, but I had no control over anything. Should I scan for rootkits? Should I even turn on the pc? Pretty scared, never seen this happen before.