Yep. This is hardware related. To be fair, many programmers I know are also into self-building and more hardware-related stuff, but that's something I personally just don't know my way around well (instead I like more theoretical computer science more). So I genuinely don't know the problem here, and I think that's fine.

The CPU is the silver squarish shape towards the right. It generates a lot of heat when in use, so having good cooling for it is important. So important that CPUs come with a fan in the box. This involves a heat sink to help draw heat away from the CPU. This screws on mounting points around the CPU, but thermal paste is also used to help heat transfer up. Then there's a fan that attaches to that heat sink, so that the hot air from the CPU can be blown away from the CPU.

People spend a heckton of money on cooling for their CPU and GPU, because when things overheat, they throttle themselves and performance becomes super slow. Longevity of components can also be harmed by higher temperatures. If it gets too bad, then it will crash entirely.

This PC has put the CPU heatsink on the case fan on the left. I don't think this is especially harmful in and of itself — the big problem is that the CPU is entirely "naked" and has no cooling whatsoever. This means the CPU begins overheating basically as soon as the PC is turned on.

Edit: you can actually see where the heat sink should match up to the CPU here

If you're a programmer and don't see what is wrong....

It’s the irq jumpers for the mca expansion card right?

My Frankenstein in an ikea drawer probably works better than that customers Frankenstein and mine doesn’t even have all needed power supplied

That's significantly worse. Assembling a PC without knowing what a cooler is for is bad enough, but to actually cut pieces off complex electronic components, I don't know what kind of state of mind you have to be in for that.

Honestly, I am envious of you, as well as the person OP posted above. You did something - learning from whatever source you could find best; having the determination and will to go ahead and sought help perhaps knowing too well you might be ridiculed. Because for the people that know this stuff, it is trivial and not worth of botheration. So the help is not enthusiastic - but for the new doer it is so challenging.

I wish I had the energy, time and courage of you all... Maybe someday I will but until then I can only love and admire your passion.

... as opposed to those ones that consume heat from the environment when they run.

It's also backwards

In the old days, before laptops, we used to call the case and everything in it the CPU. You had your monitor, keyboard, mouse, maybe printer, maybe modem, and they would all plug into the "CPU." Yes, we knew there was also a chip inside called that but we didn't get all pedantic about it.

With that in mind: Place the CPU fan on the heat sink... That's exactly what they did.

When I was in IT, had someone who couldn't get their USB printer to be detected by their laptop. They turned everything on/off and it never would show up. Even I was a little confused, so I unplugged it from the laptop, and then went to go plug it back in, but couldn't feel the port. I go to take a look, and find there's no USB ports on that entire side of the laptop. somehow they plugged the USB cable into the Ethernet port.