Enderman

Speedfan?

Get a cyberpower PFC LCD UPS, they are pure sinewave and affordable.

EDIT- nice I see you fixed it

Well none of them will offer any improvement for gaming, so just get the cheapest one.

What does the "smart info" tab show? Can you post a screenshot of crystaldiskinfo?

Put a fan blowing on it and see if lower temps make a difference?

This is a bad idea. You don't want one crash to stop everyone from doing work. What large companies do is use thin clients connected to a data server, much more reliable and easy to maintain.

The AX750 wasn't great, I had an AX860i that died and killed a bunch of parts. I only use seasonic PSUs now. Yes some materials can degrade even if the PSU is not being used, but unless it's a crappy PSU, it will take decades for the plastics to become brittle or for solder joints to fail. The first thing that will fail in a PSU 99% of the time is the fan, which is the only moving component. I think you're overestimating how delicate electronic components are.

Capacitors, resistors, transformers, etc. are designed with hundreds of thousands or sometimes millions of hours of MTBF. As long as the PSU is high quality and is designed properly without overdriving components, the PSU will last many decades. Many electronics that were designed properly from the 60s and 70s still work perfectly fine because they were designed without cutting corners and following the spec.

The 'deterioration' of components is far slower than you imagine. A good quality PSU should last 50+ years assuming that it runs at reasonable temperatures and humidity levels. A cheap quality PSU is a completely different matter.

It's literally just an address. Like it doesn't make a difference if your house number is 2567 or 2569 or 2678, it's just a number.

Do a clean install if you want windows to work properly and not have issues in the future. Just move your data to the HDD temporarily and then move it back.

All PCIe is backwards compatible.

If you look at the surface of the metal under an electron microscope you will see that even if it is lapped it is extremely rough and uneven. You would need to do 3-plate lapping with a machine or some diamond turning to get a surface that was actually flat. Thermal paste or liquid metal is ideal, as long as the thickness is kept to a minimum, which lapping helps with.

Clean install windows?