Weird PSU problem

Haygate

Honorable
Oct 31, 2013
2
0
10,510
Hi guys, having a weird PSU problem with my XP machine. I replaced the power supply & the pc was running fine but was turning on as soon as I flicked the switch on the PSU. I figured this was odd so I tested it with another psu. With the second psu everything was spinning up but the monitor wasn't receiving a signal.
So I go back to the first psu and now it wont turn on at all. The CPU fan does half a turn then nothing. I don't understand as this cpu was working fine before.
Any ideas what the prob could be?