New computer shuts down after 5secs. Yellow light on mobo

Ondas1

Commendable
Jun 7, 2016
2
0
1,510
I've just built a PC for the first time and I'm having a problem where the PC simply shuts down every 5secs.

CPU Intel CPU Core i3-6100 3.7GHz
GPU Geforce GTX 960 4gb - Gigabyte
PSU ANTEC 80+ Bronze NeoECO Classic 650W
RAM 8GB DDR4 - Crucial
MOBO GIGABYTE GA-H110M-S2H

My motherboard is showing a yellow light.

I've tested the PSU by putting a paperclip in the black and green wire, it works perfectly.

I've tried switching the RAM slots and removing it completely, it doesn't even do the beeps, it just shuts itself down after 5secs.

I've tried unplugging the CPU cable (forgot to connect it by mistake). When I do that it stays on.

I've checked for bent pins on the MoBo but couldn't find any different from the rest. They're all slightly bent facing either down for the upper pins or up for the lower pins.

Tried re-applying thermal paste to the CPU, didn't help.

Tried removing the MoBo from the case and putting it on a box.

Thank you.