Power supply failure?

Bleubird

Honorable
Nov 7, 2013
88
0
10,630
When I moved my computer downstairs to download a game via Ethernet, it turned on for a second then turned off. I brought it back upstairs to make sure it wasn't the outlet, and it still wouldn't turn on. It worked before I took it down. I took off the side panel and shorted the motherboard 24-pin, and everything turned on; the fans turned on that weren't connected to the motherboard. I'm guessing this is a motherboard problem, but I need it confirmed before I send it back.
 
Solution
It still could be power supply. It might work unplugged from mobo but when you plug it back in it gets more load and fails. shorting the pin only tests the switching circuit.