How can I get the music to play on Movie Maker 2012?

I am creating a Movie Maker 2012 slide show project of old hard copy photos. I have copied the photos into Movie Maker in the sequence I want, and now I am trying to add music from my PC. I select the Add Music tab, and then select the From My PC tab, and that brings me to My Music folder where I highlight the music I want and select Open. A green line appears under the photos in my Movie Maker slide project.  When I play my project, the slides appear nicely with my captions, etc., but there is NO SOUND. No music is playing. What do I need to do to get the music to play?  Thank you very much for your help.