I use Windows XP as my OS and this is what I do.

1. Copy the  music I want to use as a file into My Music from my CD drive, if not there already, naming CD track files.

2. In Photostory slideshow, click on the bottom left hand button to open the 4 tracks ( Slides, audio 1, Titles, Audio 2).

3. Go to the right hand panel and open Media, My Media, My Music and your music files should show up.

4. Click and drag the file onto either of the audio track bars ( I use the lower one, and put my commentary on the second bar underneathe the slides.

5. Success will be  if a sound track graphic opens up in the selected track.

6. If more than one track is needed for the story, select another and click and drag it to the end of the first track.

Hope this helps, Pete