O.K., so I've got a file called iTunes Library.itl dated 11/14/11. Do I trash the current file, and move the November 14th file to where the current one is now?

If that will work, I should be able to reconstruct what's happened since with no problem.

Do I need to trash the old file, or can I just drag it to the desktop?

As for the "update," I don't ever remember having one before, so I thought it might be some kind of malware. Guess not. frown
"Seek for the merit in others, even the tiniest shred. Then do the same in yourself"
-Reb Nachman