I'm helping a friend fix his computer he says that he left is computer on one night and came back to it off in the morning, He tried turning it back on but apparently smoke came out the back and it turned off I'm just making sure this is a Psu problem. I do have access to the computer to provide extra details. I have opened it up cleaned the damn dust demon out and opened the PSU to see if there were any explosions I couldn't find any unless some white substance is not supposed to be in there it is mostly around the capacitors