Reinstalled Windows 10, and Joplin and it does not see the Joplin data directory, which is in my AppData\Roaming directory on my D drive. I followed instructions elsewhere in the forum to copy the directory to .config, and the prog still doesn't see any data.
This path is only used for Electron temporary files. They have no value in terms of the actual data (and are regenerated automatically if you remove it).
The actual Joplin data is stored in %USERPROFILE%\.config\joplin-desktop (just copy and paste the path into the address bar in Windows Explorer, then press Enter). I only hope that you did back this one up before reinstalling Windows, or otherwise, the previous notes are basically lost…
Should add, all was not lost because I only fairly recently imported enex files from Evernote, so I was able to reimport. And most of the other stuff were copies of p/w's from Lastpass. Thanks again for responding so promptly