Alright, I had a computer that was working perfect but recently it failed to power on at all. The system starts and immediatly shuts down again. So I get another power supply and plug it in and it works but the screen is blank. No Signal. I get another motherboard and use that, same thing no signal. All this time I've been swapping out RAM and hardisks so those are not the problem. Then I take my original power supply and plug it into the new motherboard...and it works but there's still no signal. Now I'm completely clueless. Are there any tests to test to see if the motherboard is working or any tests to find out of the processor is working. Also if the processor isn't heating up could it not be working. Usually if I don't keep a heatsink on top of the processor the computer shuts down to overheating. I switched to different monitors too... And, is it possible to run without a processor just to like the BIOS screen or something at least. Could you run without a processor and get an error on the screen at least?