Question PC Unresponsive to Starting Up - Totally at a Loss

Jan 22, 2020
For a while I was getting crashes on my PC playing a particular game that seemed to indicate an issue with power getting to the GPU. I underclocked the GPU and CPU a bit and it seemed to resolve the issue. After a few weeks, however, the PC totally locked up, so I held down the power to turn it off. When I booted back up, there was nothing in the events of reliability report about the crash. Less than an hour later, same crash, except now the PC will not turn on, no response whatsoever when hitting the power button. Below I'll list what I've tried so far.

New Power Supply

My initial thought was to swap the power supply, so I bought the exact same one. Swapped it (new cables), no help. It was only after this that I learned about the paperclip test, so I tested both new and old power supplies, and they both passed. I stripped out everything from the PC except for MOBO, CPU, RAM, and I think harddrives (one SSD, one HDD), and tried again. The power supply fan would kick on for maybe 5 seconds, and then turn off for a few, and repeat indefinitely. I was able to repeat this result with both the old and new power supply (used different combinations of cords and wall outlets). I figured it was something else, so I returned the power supply I bought.

Next assumption was MOBO, but finding an equal replacement was more expensive than getting a new one, so I replaced/upgraded MOBO, CPU, RAM. Swapped everything, and fully attached all components (GPU, hard drives, etc.), and same result - no response to the power button. Next was to disconnect everything, including drives, and try again - same result. Paperclip test still works on power supply.

I'm at a total loss. Not even sure what I can test next, or how to do it. If it's somehow just my case...

Original build: (capture card is

Replacement parts:

Any ideas would be greatly appreciated.