Wife’s PC died and totally refused to turn on, removed GPU and switched to IGPU and it now seems fine, how do I confirm it’s truly the GPU that is the issue?

Hey everyone. So, question in title. I think I have a way forward on this but I wanted to confirm and make sure I’m not missing anything.

So my wife’s PC went bad, just went off randomly one day. It refused to turn on afterwards. You’d press the power button, things would start going for a split second, and then power off. Absolutely dead. I tried removing the GPU (EVGA GTX 950), switched to the IGPU on the motherboard, and powered on again. It booted up fine. I replugged the GPU and tried booting up, totally dead.

My first inclination is to think it is the GPU itself. I inspected it as best I could but couldn’t see any visible signs of it going bad, looking for blackened areas or popped capacitors, though I’m not particularly well versed in what to spot. However, I suspect it also could be either the PCI-E slot or the power supply’s 12V rail going bad.

I don’t want to rule out the GPU as dead until I know for sure. Do you guys have any suggestions on other steps I can take to rule out other possible explanations?

Thanks.

Edit: Definitely the GPU. I plugged it into my PC that has all known good components and it fried itself when I pressed the power button. Thankfully the damage was just the GPU, my PC remained fine.