While I'm here if you want to save a System Image backup and Clean Install, or shrink C to Clean Install in a Dual Boot to compare, then I'll help you try to resolve any issues.
Thanks, Greg, for your offer regarding a clean install (after a System Image Backup). Believe it or not, I actually have a complete backup which I did yesterday ... I do that about once a week. I could try (successfully, I'm sure) the clean install but don't want, at least right now, to spend the 5 or 6 hours required to put it back together and install all additional software. Regarding the Dual Boot, the hard drive is only 256 GB, and I don't wish to place two partitions on the drive as both, probably, would be too small. I happen to have a 512 GB SSD which I've never used and I guess I could try that one in the machine, using Macrium Reflect to clone the drive I've been using and trying it but I'm not sure I want to Dual Boot it ... I get impatient (as I tell my wife, I am not a medical Doctor and don't need patients ... my PhD is in another field).
Again, thank you, but in this case, I think I'll pass.