I ended up trying the upgrade from Win 7 to 10. I did NOT want to do a clean install, because even though I was able to copy essential stuff to an external drive, didn't want to spend hours putting things back where they belonged, nor reinstall all my software.
I tried to upgrade, and got the "we couldn't update the reserved system partition" error. PIA! After lots of research, tried a third party software option, followed the directions, but something went ary, corrupting my $mft. Couldn't even re-boot, because it'd hang saying I needed to run chkdsk and that the $mft was corrupted. The only Windows 7 disc I had was for a wipe and reinstall to factory new - again, not what I wanted to have to deal with.
After much hassling, cursing, I realized that I still had the original hard drive that the laptop came with, having cloned it onto a more modern SSD. I was able to reinstall the original drive, create a rescue disc, put the newer (corrupted) drive back in and boot from the rescue disc. Thankfully it was able to repair the damaged $mft and whatever else was wrong, and I was finally able to update the system. Total time spent on this upgrade: about 6 hours. I never want to have to go through that again, just to strech some more time out of an 8-year old laptop (I have more pressing things to spend $1000 on instead of forced computer replacement).