windows 10 Cannot Open or View ANY disk drives or change settings in Explorer!

[Vern11]

All of a sudden, when I try to view any or all disk drives by double-clicking their icons on the desktop, NONE of them will open or display. What I always get instead is the error message: "Windows cannot access the specified device, path, or file. You may not have the appropriate permissions to access the item."

I get the same error when I try to run any *.msc or control panel. When I choose Settings instead of Control Panel, nothing happens at all. I get it even if I simply double-click "This Computer"!

I'm running 64-bit Windows 10 Pro 1803, and since there are no other users, my user account is an administrator account. Which means this almost certainly isn't actually a permission problem at all. Even if it was, since I cannot open any disk drive, I can't examine or change the owner/permissions.

When I looked up what might be causing this error, none of the alleged "explanations" fit what I'm seeing. Here's what Microsoft has to say about this error...

1: Check the permission of the file or folder: I can't! At least not in Explorer.

2: Check the file location: There can be no doubt as to where my disk drives are!

3: Make sure that the file has not been moved or deleted: I know with certainty that my disk drives are right where they've always been.

4: Recreate the shortcut to check for corruption: These are not shortcuts.

5: Unblock the file: My disk drives are not "blocked".

6: Check to see if your antivirus software is blocking the file: Due to an unrelated issue (some process was deleting a few Nirsoft.net executable files whenever I extracted then from a zip file - I have now solved that), I have uninstalled all anti-malware tools on the computer in question. In fact, the very reason I booted up was to re-install them, which I obviously cannot do when Explorer can't find any of my disk drives! In any case, I ran the latest MBAM and found no malware.

For the heck of it, I ran SFC, and it didn't find any problems.

What's going on? What can I do?

Thanks!