The PC (motherboard) does not start, what should I do?

Question

Batteries

Good afternoon !
I run the PSU on an office computer - Fujitsu / Simems, and instead of starting, only endless clicks of the motherboard are heard. The light comes on and immediately goes out, simultaneously with a one-time operation of the fans. I turned off all the spare parts in turn, until my mother was naked. Problem still exists. I also changed the PSU to an identical one, changed the motherboard and processor. Incompatibility is excluded, since I worked with similar parts for a year.
The situation is completely hopeless!
Tell me please.

Answer 1

Short circuit on 12v lines in the processor power phases.
Check all capacitors and replace a broken field or two or everything, as you're lucky.