Ebay, Facebook market, craigslist, used on amazon. Any platform where users can rate/review the seller is preferable, but really CPU's are pretty hard to kill.
Hopefully devs see that more people are going to be stuck with aging GPU's and that'll motivate them to optimize games.... I know it won't but its a nice thought.
That small SSD is certainly suspect to me, 240gb is as small as I would go for a boot drive these days.
Verify the health of your HDD with crystaldiskmark or some other software.
I doubt your PSU is at fault, but i suppose its possible
wrist rest might help, vertical mouse might help. I use a vertical mouse for work at I don't really think about it, granted I've never had any hand issue so far either way.
Good that you're seeing a doctor, I imagine they'll probably suggest the same thing we did although "issues" is quite a...
Try a different USB port, and visually inspect the USB ports.
Run crystaldiskmark or some other drive health checker if windows is installed on an HDD, ive seens lots of weird issues from failing drives.
reset BIOS.
eh its fine. Obviously sharp bends have to potential to eventually damage any cable/plug, but modern PSU's are pretty sturdy.
You've already installed it, I wouldn't worry about it too much as long as the pressure isn't going to make either of those plugs wiggle loose.
Better single core performance on paper... dual cores are certainly not something worth looking at if you're doing anything above web browsing though.
I honestly would ignore quad cores that don't have hyperthreading as well.
I would point fingers at the motherboard. Your CPU temps are quite high but as far as I understand are within intels specs. I do see that other users have noted instability related to temps though.
You should clear your CMOS. Its easy and pretty much risk free. Just unplug your computer...