Windows Store couldn't install, "We'll retry shortly", fills hard disk with events in temp directory

I'm using Windows 10. A couple of months ago I tried to use calculator, and Microsoft Windows said this Microsoft Store app couldn't install. That was strange, because it is installed by default. I went into Windows Store and uninstalled it and then tried to reinstall it, but nothing would make it work. It kept giving an error. So I installed a third-party calculator.

Yesterday I realized that my system temp directory was full of tens of gigabytes of files. I brought up the system event viewer, and there were lots of messages like this:

Installation Started: Windows has started installing the following update: 9WZDNCRFJBMP-MICROSOFT.WINDOWSSTORE

and

Installation Failure: Windows failed to install the following update with error 0x80073CF6: 9WZDNCRFJBMP-MICROSOFT.WINDOWSSTORE.

So I tried to start Windows Store, and it wouldn't even start! I've tried everything:

• I've gone into the Windows Store app settings and told it to reset.
• I've ran wsreset.exe; it gives an error about PurgeCache. I tried several times, and now it gives me a notice dialog saying, "You'll need a new app to open this ms-windows-store."
• I've ran the Windows Update troubleshooter; it finds no problems.

Now I repeatedly get a Windows notification alert saying that "Microsoft Store couldn't install". It also says "We'll retry shortly."

Now my system event viewer is continually filled with things like this (each line is a different info/error event):

Windows Update started downloading an update.

Installation Failure: Windows failed to install the following update with error 0x80073CF6: 9NBLGGH1ZRPV-KING.COM.CANDYCRUSHSODASAGA.

Installation Started: Windows has started installing the following update: 9NBLGGH4QGHW-Microsoft.MicrosoftStickyNotes

Installation Failure: Windows failed to install the following update with error 0x80073CF6: 9NBLGGH4QGHW-Microsoft.MicrosoftStickyNotes.

Installation Failure: Windows failed to install the following update with error 0x80073CF6: 9PHNB71MKR4J-king.com.BubbleWitch3Saga.

I don't even want all this stuff. Apparently it's trying to download and reinstall all the preinstalled Windows Store applications and failing. It's continually doing this, filling up my hard drive with temporary error message files. Now these events are taking up literally 99GB on my hard drive in C:\Windows\Temp!!! I still can't open Microsoft Store.

I don't even want Microsoft Store. (Note that I never was logged into Windows Store using a Microsoft account, and I don't intend to.)

I have all Windows 10 updates installed except the latest feature update build 1903, which Microsoft has told me not to update to yet because of the bug with attached USB drives (and my laptop has USB drives built in).

How can I make it stop trying to download and reinstall Microsoft Store?

(On a related note, is it OK if I go into C:\Windows\Temp and manually delete the almost 100GB of *.evtx files that are being generated every time Windows Store tries to download and fails? I already tried "Disk Cleanup" with "Clean up system files", but it didn't remove these files.)

You just have to:

1. right-click "My Computer" and click Manage.
2. go into Services and Applications, then into Services.
3. find Windows Update.
4. turn it to Automatic and click OK.
5. go into Windows Update again.
6. select Start under Service Status and click OK.