Computer turns on and off constantly when turned on

AlfredTee

Honorable
Nov 9, 2013
7
0
10,510
I've looked all over the internet to figure out the problem, but nobody seems to have the exact same problem.

What's happening is when I turn the computer on by the power button, it turns on for about 5-7 seconds and turns itself back off again, but it does this constantly until I manually switch it off. Nothing comes on my monitor besides a black screen of nothingness.

The problem started randomly after I opened the side of it to get a view of the inner components due to needing a new graphics card. Nothing was taken out or interfered with.

I called the manufacturer and they asked if I know about the innards of a PC, I said relatively and they said to try and diagnose the problem myself.

Any help would be greatly appreciated.
 
First part to test would be the PSU, make sure all connections are firmly placed, then turn on the pc and try getting into BIOS and watch for its voltage values, alternatively you could test it directly with a multimeter.

Also if possible, try borrowing a PSU and try booting your pc with it.