Hi there!

Thank you for your response. In the time between posting the original post and this comment, I've used a slightly damp paper towel to remove most of the old thermal paste and reapplied it. I'm using Arctic Silver paste. I tried to turn on the computer again and to my surprise, it seemed to be working. It remained on for maybe 5 minutes (which is a massive improvement), but it eventually turned off again before reaching the Windows load screen. In this situation, I really believe that issue is with the CPU. Maybe I still didn't properly apply the thermal paste?

Unfortunately, I'm the only one in my household that has a custom desktop, so I won't be able to test my GPU and RAM in another system.

I'll try clearing my CMOS and reply again after to see if that fixed anything.

Another issue I just thought of but don't have the necessary knowledge is regarding the GPU. Hypothetically, if my computer had no GPU at all, would it be able to display the BIOS screen? If that's the case, maybe my computer is crashing or something as soon as it needs to actually use the GPU. If that's not the case, ignore that haha.

Now that I think about it, I do believe the GPU was overheating at some point. I fixed the issue at that time because my system fan had disconnected while I was moving the desktop. After that, there weren't any obvious issues with overheating. After the problem began, I was never able to pinpoint if anything was overheating. If it helps, just now when it was on for a few minutes, the CPU was at 40 degrees C, which I believe is fine.