Win10 Update Problems

Naturally it's unfortunate upgrades can be difficult sometimes, I guess for the minority of the sum total of Windows users, and I also find the available support for resolving problems significantly lacking, not to mention the usual obscure error messages or logs.

You are exactly correct about the un-"available support". I've been in contact with Microsoft technical support repeatedly over about the last year about a broken Windows store and the inability of this machine to take, and keep, updates. These weren't brief conversations, either., and I had even less success with their online support. All I managed to get out of them were a couple of links to fixing a broken Windows store that I had already found, and that did not work. They were either unable or unwilling to even address the inability of the machine to properly take updates (gee-I never heard of that).
Your first response to me was more informative and helpful to me than all the calls to Microsoft were. I truly appreciate all the help that you've offered, and the patience you've shown.
I believe I've got all my ducks in a row for the in-place upgrade, but won't have time to do it until this evening. I'll report back after it's done.

I LIKE your sledgehammer approach! It worked a treat! I have imaged the latest drive C after the successful in-place upgrade. I expected to find some windows quirks, but haven't found any yet. I couldn't be happier! SFC /scannow can find no problems, to the point that it finds no need to create a logfile. Thanks expecially to dalchina for all his excellent advice and his special patience. I hereby name him an honorary Texan, simply for coining the sledgehammer approach, something any Texan can appreciate. This also fixed the Windows Store, which hasn't worked on this machine for over a year, and for which Microsoft had no solution.
So for further updates/upgrades, what would you suggest? Just allowing nature to take its course, or should some sort of forced update be performed?

When you perform an upgrade if it works you will have completed the troubleshooting.
If there are problems with the upgrade we can troubleshoot the Panther logs.

Consider making a backup update image with Macrium and a brand new restore point before the upgrade.

Consider making a backup update image with Macrium and a brand new restore point before the upgrade.

Already done.
Rather than approach this from a direct upgrade with the disk, I simply downloaded the upgrade assistant and set it to work. It's currently downloading and we'll see how it goes.

While I'm thinking about it, the upgrade install appears to have added a NTFS (?recovery) partition to the C: drive. Normal?

Okay, now on Windows version 1709, Build16299.64 . I've not noted any major glitches, but I note that a few things will have to be reset. Just housekeeping stuff like turning the trackpad back off, re-adjusting the keyboard backlight, stuff like that. There are still only the 2 previously noted recovery partitions on C: I've got a new restore point and I'll do a new image of C: tomorrow. It'll be interesting to see if this update has messed up the usual culprits and caused problems with hibernation and sleeping. That's been a problem with this machine and prior minor updates. It has been an issue with an IMEI driver, but I think I may have gotten that resolved in the past. We'll see if the fix survived the update.

So far, the only "snag" that I've managed to find is the disappearance of Asus Smartgesture from the startup programs. Without this installed, you can't turn off the touchpad via the function keys. The touchpad was continuously on, making typing difficult with the cursor mysteriously jumping around in whatever text you were trying to type because of my normal hand positioning. A simple reinstallation of smartgesture fixed that.
The average boot time has improved, as well. From an average of 42 seconds while on 1511, to an average of 32 seconds on 1709. Not too shabby when you consider Windows and my admittedly bloated startup programs use just over 4 Gb of memory once the bootup is complete. I don't know how much of the improvement is from 1709, and how much is from cleaning up all those partitions on the SSD, but I am pleased.
The upgrade also fixed a chronic problem that I had thought I'd have to live with. I could sleep or hibernate ONCE per boot cycle just fine, but the second time you tried it, the screen would go black, but the computer would remain powered up. You COULD NOT get the screen back up. Required a hard power-down. Not any more. Now I can sleep or hibernate as many times as I want per boot cycle, and everything works as it should.
I've done just about everything I could think of to stress the OS. I've had 5 or 6 desktops operating at once with things like autocad, corel draw, photoshop, a browser with a big web download, VLC with a HD movie going, etc. Not a burp or hiccough.
I am very delighted, and IMO, the work required to get here was more than worth it. I owe a big debt of gratitude to those that contributed their assistance, most especially dalchina.