Warning: I installed Ubuntu manually. 18.04 is installed, and when I run it manually from the Windows 10 PowerShell it opens. When I attempt to open Ubuntu in the Programs list by clicking on the Windows logo and clicking on Ubuntu it fails with the message above. If I open services I see nothing for Ubuntu so the fail makes sense. There is a longer error note as follows: C:\Program Files\WindowsApps\CanonicalGroupLimited.Ubuntu18.04onWindows_1804...\ubuntu1804.exe above the fail. I follow all this to double click on the executable and a window flashes open and closed in a millisecond. Uninstalling and reinstalling results in the same behavior. I had to stop working 15 years ago so I'm no longer well versed in Unix or Windows much less Linux. If you have an answer please phrase it as you would for a junior high school student. Thanks.
Turns out that WSL was never meant to run anything other command-line Ubuntu. I was referred to a Microsoft page which said Gnome, etc. will not operate under the Linux Subsystem; it was never intended for that.