Apple updates its iTunes application from time to time and it's important that you upgrade as new versions are released. Unfortunately, an upgrade can sometimes go awry, causing your entire music library to disappear. Realize that if your music is missing, it doesn't mean that your collection has vanished into thin air. Learn how to recover your music with a few basic steps.
Click the Windows "Start" button.
Type into the Start menu search box the name of an artist you know for sure is included in your iTunes music collection. If you locate a song by that artist on your hard drive, you will probably find the rest of your music library because all of your songs are stored in the same folder.
Navigate to the folder containing your music and import your library back into iTunes. Click "File" in the iTunes application window, select the music files you want to import and press "Enter."
Force iTunes to look for your songs and import them manually if the above method fails to recover your lost music. Make the iTunes window smaller so you can see a good portion of your desktop. Click on the "Start" button.
Locate your "C:" drive and then drag and drop it into iTunes. This will force iTunes to search your hard drive for any content that it can import. If your music is on your hard drive, this will put it back into iTunes.
The only drawback to using the drag-and-drop method described above is that all sound files on your hard drive, including dings, bells and alarms will be imported into iTunes along with your music. You will have to manually delete these files from iTunes, but at least you'll have your music back.