Question Computer issues - PSU? GPU?

Oct 17, 2020
Looking for some advice. Maybe someone had similar issues in the past and could suggest what is wrong with my computer.
Long story short, about a week ago I had my computer just randomly turn itself off (2 different occasions, 2 different days). Initially I didn't think much of it, thought maybe I knocked the extension or accidentally pressed the restart button with my leg (I sit like a dummy). On either occasion I wasn't doing much, one was playing a not demanding game and the other I was just chatting to friends on discord.

So we go forward to the feral day (this Thursday) where the PC turns off again. I want to make a note that each time it's only the pc and it seemed like it lost power for a few seconds. I had a spare extension lead so I decided to replug the entire thing, and as I go to boot up the computer - nothing happens. I think to myself fantastic - it is dead. No, it can't be. All the rgb leds etc are still lighting up on the motherboard, so it is getting power, something is working. So I spend the next hours trying to plug, unplug and reseat parts like gpu, ram.. Nothing seems to be doing it, until I eventually discover that if I push and hold my gpu (towards the motherboard) it allows the pc to turn on, I would get no display on my monitors though and also my motherboard has the white led light on (which symbolizes GPU problems).

So my immediate diagnosis is that the GPU is broken, so with that in mind I keep doing more stuff to test it out, pushing it in, letting it go. Eventually since I figured it is probably the GPU that's having issues, out of warranty - I opened it up, changed thermal paste and cleaned it up a little and plugged it back in. PC works! Displays don't work again, but the booting doesn't seem to be an issue now. So I turn the PC off again and decide OK, I'm gonna unplug some stuff to see if maybe it needs more power.

Tada it worked! And now we are here. I'm sort of in between being ready to say: it's gpu. it's psu. Damn for all I know it might still be the motherboard, but I feel like that's unlikely.
I am on the computer right now, there doesn't seem to be an issue with anything really, except my sound being fuzzy (ha, new thing I gotta figure out now).. I do however have a bunch of things unplugged right now, including my oculus. I would say the power if on the more preserved side, that being said I also did fiddle around with the gpu earlier. .
I am okay with replacing the faulty part, if I just knew what exactly is that I am looking for: a GPU or a PSU?

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