It turns out Privatefirewall was causing the problem with my Windows Update. I checked the service for my Windows Store. It's set to manual. And that setting is blocked out so it can't be changed.
No Privatefirewall doesn't work with Windows Firewall. I keep Windows Firewall completely shut down. But the Privatefirewall thing actually fixed the problem.
It's weird. I had it shut off when I was doing all these tests. The store wasn't working. Likewise Windows Update was stalling on checking when used either from my MSA user account or from built-in Administrator. In the built-in Administrator account, I turned on Privatefirewall, and Windows Updates worked. I uninstalled Privatefirewall altogether, and everything just started working. Even the Store. Now I'm testing out Zone Alarm.
I'm not comfortable using the built in Firewall because it might let stuff in and out from MS. Like Private Firewall told me about "wsqmcons.exe". Something in Windows that tries to access the internet. Which Windows Firewall probably would have let through. I found out what it was - a Customer Experience Improvement goblin-process. I was able to go into Task Scheduler to disable it. If not for the third-party firewall, I probably wouldn't have known about it.
This is the whole reason I keep the Windows Firewall completely shut off, and use third-party full firewall. Hopefully Zone Alarm does just as good a job as Privatefirewall without the glitches.
I've run into just about every problem encountered by everyone previously posting, plus more. To keep this short, I'll only mention the differences. I was on the Fast Track of Microsoft's Insider Preview, but after the most recent preview update rendered my laptop close to inoperable (it would never completely shut down, and booting/rebooting failed at least 90% of the time, leaving me with a black screen), I first rolled by my Win10 install to the last official build (Ver. 1511, Build 10586.36), and then removed myself from any further Insider Preview builds. Unfortunately, I discovered (only yesterday) that the Microsoft Store, as well as any apps related to the Store (Calculator, Calendar, Weather, etc) no longer function. As with others, I get a "flash" of the outline where the app would appear, and then it's gone. Talking with Microsoft's tech support was useless, even after going through PowerShell, etc (as described throughout this forum. I believe I've finally tracked down the problem, but as for a solution, I haven't the slightest clue.
To the best I've been able to figure out, while Windows was restored to the previous build, the Microsoft Store, as well as all Store apps having been updated to versions newer than the "official" release, remained as their "newer" version. Just to mention a few, as an example, the Store folder within the WindowsApps is labeled as version "2015.25.5.0", while the version attempting to be installed (and failed) from the reinstall-preinstalledApps.ps1 file is "2015.2323.4.0". Likewise, the version of Windows Maps, as shown on my computer, is version "4.1512.3450.0", while the reinstaller package contains version "4.12.11000.0". I could go app-by-app, stating the "newer" versions shown on the laptop, against the "older" versions included within the reinstaller package, but I'm sure you get the picture.
I've tried every PowerShell option, and it's all failed. I've tried performing an In-place Upgrade, and, due to the first two options (especially the first option) being grayed out, that's not a possibility. Through the "assistance" of Microsoft's phone-based tech support, I've even attempted to uninstall the Microsoft Store, and all related apps, so as to install the Store, as well as the apps, from "scratch", but, as with everything previously attempted, all has failed. I'd REALLY prefer to avoid doing a clean install (if EVERYTHING fails, I guess I'll have no choice), but I am also close to the "end of my rope", so to speak. What else is there left to try, before the "last resort clean install"???
Any/All help is appreciated.
The Powershell method won't work as you can read from post #83 and later in this thread:Store - Re-register in Windows 10 - Page 3 - Windows 10 Forums
1) If you have a computer that was originally running something other than Windows 10, as with any previous upgrade (ie. from any older Win OS, to a newer one), when you upgraded, there were files leftover from your previous OS, not to mention a lot of garbage left in the registry. In performing a clean install, your system is just that.....clean.
2) If your system (as is the case in almost all computers these days) came with a partitioned hard drive, which wastes storage space (especially once you've upgraded the OS, and those partitions contain data that no longer applies), performing a clean install is your chance...better yet, "opportunity"...to get rid of those space-wasting partitions, and utilize the entire hard drive's capacity as a single partition. The only realistic reason I can see for having a partitioned drive is if you're running a multi-boot system with more than one OS. Long gone are the days of partitioning your drive into multiple "drives", especially considering the cheap price of both traditional hard drives, as well as SSDs. Today, you can purchase a 1TB SSD for the same price you'd have paid for a traditional 60GB hard drive back in July 2000.
3) If your computer is still utilizing a traditional hard drive, this is also your opportunity to replace it with an SSD, which will speed up your system in many ways. Just using boot-up time as an example, my Lenovo Y50-70 Touch, with a 1TB Samsung EVO 850, boots up in less than 10 seconds (slowed from 6-7 seconds due to anti-virus software). If you're complaining about the cost, suck it up, and just go buy it...you WILL be happy you did (especially the gamers out there who can't afford a "boutique gaming laptop).
Now, time to prep for the clean install......................