PC won't turn on unless powered off for a while

[Ridguard]

Hey everyone.

I've got a fairly old pc (about 7 or 8 years) and I've got a problem where when I turn the system off, it won't turn back on again unless its been unplugged for about half an hour or more..

It's happened twice now, tonight after I updated and shutdown the pc, and once just over a year ago where I can't remember exactly what happened, but I think it powered off unexpectedly and I guess I incorrectly thought that a new lighting strip that I had plugged into it (for a shelf) had shorted something.

 

I've tested the power cord/power strip/wall socket, all are fine and I don't really have the ability to test anything beyond that (medical issues, also lack of know-how), have also confirmed the behavior twice tonight of it not powering back on unless its been unplugged for 30min+.

Oh also, It will do a restart just fine without any issues.

 

My system runs 24/7 and besides this I don't really have any issues with it, pretty stable.

Specs are i5-4670k, Asus Z87-Pro, 16gb ram, RTX 2070. I replaced my old gfx card about 2 years ago, didnt have any problems at the time.

I can't remember what my PSU is, I can't really get to it myself, but I know it wouldnt be underpowered.

 

Is this most likely a PSU problem? And is this something I should get looked at immediately, or should I not worry too much about it for now?