Well...I put the new computer together (hardware and software) and everything went well. Its much simpler nowadays than back in the 90s and earlier. However, I then realized some of the minor stuff (like plug ins and utilities) can't be activated because they are older (and some companies are out of business or the servers don't work...that sort of thing). So its quite disappointing and trying to figure out how to deal with that...which means I need to keep attempting to fix the old computer.
From a historical perspective, I had some computers totally "fail" back in 3.1 and Win95 days. Less so in Win98 and I don't think anything I couldn't recover from since Win2000 and later (until recently). Recently, they started to take more control over things, which is good in some ways, but was really bad in this case. In fairness, I should have had an image to recover from, but it had been 20 yrs since any serious issues so I figured it was low risk. This failure was totally on Win10. Removing a secondary disk shouldn't cause it to automatically spiral out of control. All it had to do (like in the past) was just not boot. Then I would have put the disk back and made an image that point (or 2 images). I would have then determined if there was a dependency on the second disk. That way I am safe...more or less. However, it just started doing all kinds of stuff without my permission and really made a muck of it. Putting the second disk back in didn't help at all. Oh well..,back to seeing if I can get the old one up and running again.