If you were previously using Firefox Sync, there might be some recoverable data associated with your Firefox Account, which would be encrypted using your Firefox Account password from the time the data sync'd.

Assuming you already connected your new installation of Firefox to your Firefox Account, you can install the following add-on to see what is available:

https://addons.mozilla.org/firefox/addon/about-sync/

After installation, type or paste about:sync in the address bar to load the add-on's page showing what is in the Sync cloud for your account. Any bookmarks there?

Thank You so much for your reply. When I do the "about:sync" it brings up a mostly gray screen w the only reference to Bookmarks being under something called "Collections." However I don't see any old actual Bookmarks under that sub heading

Under bookmarks, does it have a little row of mini-tabs and information along these lines:

"Downloaded all 278 records (2 deleted)"

To see the actual records, you can click the little tab labeled Records (table). For me, this is absurdly wide so I can't see any columns after the URL, but I can get a sense of what is there.