I have some issue on a computer, and after several tests I found out that the only way to safely turn on the computer (otherwise it is dead) is to keep the paperclip on the atx connector and push the button on the front panel. This is the only way to fully boot the computer. After the computer is booted, I can take out the paperclip. The motherboard has already been replaced once. It is a PSU issue? What is going wrong?