Within iTunes under the File Menu is the “Add to Library” command, which allows you to select entire files. So if all your songs are in your Music file highlight it and click the “Choose” button.

Wouldn’t that just add another copy of the songs to the library? Besides, the new copy of the songs are not going to be link to my playlists. I want to relinks the songs to my library so they are managed by my playlists.

Ha!! Hey, Calvin! I didn’t realize this was you! This is Kat from iRovr.

If you lost your music, didn’t you lose the playlists, too? If you put all the songs in your Music folder and copy it, it will add only the songs that aren’t already in your Library. You can always confirm by having iTunes look for duplicates. To the best of my knowledge, you will have to set up your playlists manually.

not sure if there is a specific fix but try this:

http://dougscripts.com

Doug has over 400 installable Applescripts that handle all kinds of useful tasks for iTunes (esp. removing dupes).

Hope this helps.