James-
Happy Ending.
I went to Norton Systemworks 2001 Unerase File Utility. I asked Norton to search for a file with the name of one of my contacts. Apparently, when I last used Sidekick, it deleted or placed a copy of my SDB file in the Norton protected deleted files bin, either as part of a normal process when I edited the SDB cardfile, or as a part of the file being corrupted.
Norton restored the file from a few days ago from the deleted file bin, and I am back in business, with backups now made!
I am still the Duke of Wellington, and not yet Napolean.
Cheers