PSU or Motherboard issue?

MylesB93

Honorable
Feb 3, 2014
12
0
10,510
A few days ago my PC switched itself off and since then, when I press the power button It'll either boot up but none of the peripherals will come on, or it'll switch on for a split second but then instantly switch off, not coming back on unless I switch the button on the back of PSU off and back on. Would this be down to a fault with the PSU or the Motherboard?

Specs:
CPU: CPU AMD FX-6300
GPU: Nvidia GTX 770
Motherboard: Sabertooth 990fx r2.0
PSU: Corsair CX 600w