Crash, then no picture

Hi!

So my PC crashed yesterday when I was playing CoD. I had to go to work anyways so I left it, today I tried powering it on and I'm not getting a picture output. The backlight of the monitor powers, stays on for about 5 seconds and then dims out again

I plugged in my onboard graphics and I did get an MSI logo for about a second before the screen went black again.

GPU fans do NOT spin on start-up when my monitor input is set to the GPU, when my monitor input is set to the onboard graphics however, the fans fire up.

This makes me pretty sure that I'm dealing with a PSU issue, but I am fairly new to building so I could use some other opinion here.

Cheers