Computer starts for about a second then shuts down

iPhasleee

Honorable
Nov 6, 2013
4
0
10,510
Stupidly, I was installing something into the motherboard about a month ago without completely disconnecting the power first. The computer would turn on and off when I was doing this. I got a tech support guy to come have a look at it and he said that it was the power supply because the fans should still spin if it wasn't. So I got the psu replaced under warranty and installed it today but it still didn't work and im still facing the same problem where it will turn on for about a second then shutdown and is completely dead after that. I have to turn the psu off, wait for the motherboard lights to shut off and then turn it back on only for the same thing to happen again.

Could I have fried the motherboard? It took them 7 weeks to replace my psu I don't want to have to go through it again with the motherboard in case it isn't that. Please help!!