Question Pc turns off after 2 seconds

[hyrixx]

Hello so my friend just got a problem in his pc that stays on just for 2 seconds after he clicks the power button then it goes down can you guys help us to figure out which part is making the issue
the pc working perfectly fine before

just a note : the electricity in his house was going down several times but that was 2 days before the issue so I thought it might be the psu but I'm not sure so what do you say about that guys ?!

 

[Phaaze88]

Full PC specs, if you know them?

Has the psu been taken out and the paperclip test performed?