nickalexkrier

Honorable
Jan 18, 2013
2
0
10,510
so my computer shut off the other day i was in the room and just watched it. now it wont turn on at all, no response when i hit the power button. what do you think is that matter? i switched out the power supply but im not sure if its a functioning one. same response with the new used one
 
I would suggest breadboarding (take all components out of the case and connect them) with minimal parts first. First issue is usually power supply - but it could be any of the components.

Try with minimal RAM, no hard drives, etc., and see if it boots. If it doesn't - you may have a defective motherboard.