Possibly PSU problem

[ColinY12]

Hi,

I have a workstation that is failing. When I switch it on it powers up for about 7 seconds and then powers off again. My intial thought was that its the PSU. I have tried swapping PSU's and the machine powers up but there is a black screen.

It is really confusing, on the original PSU i used a paper clip to test the PSU and it powers on fine and does not switch itself off.

Could somebody help me?

Thanks,

Colin

 

[ColinY12]

Thanks for the advice, I managed to get the machine powering on ok and not turning off, i think the CPU was getting too hot. However now nothing displays on the screen and the keyboard is also flashing on and off. Would it therefore be to do with the graphics card or possibly the motherboard?