The memtest is a waste of time since you aren't having memory issues. The hard drive test is useless to attempt since the hard drive doesn't even show up to be tested.
I had assumed this was a newly purchased system but see that you say it took tech support months for them to get back to you. Do you have any idea whether the 500GB drive EVER worked?
This machine was purchase July 3 2019. It was not even on at all for a month during august and early september, because my rich aunt paid to fly me up to new hampshire
to help care for my parents, who are now dead.
I'm too depressed to look right now, but I'm pretty certain this thing only had a 30 day warranty, if any.