Movie Maker not saving project correctly – getting black video screen and only audio

I have Windows 7 ultimate on my laptop.  I'm using Window Movie maker as I have in the past for an end of the year DVD for my Kindergarten class gift.  My project file works great, but it is not saving into the movie maker file.  When saving in either file format, I only have audio.  The video screen is black.  All pictures and video are accepted file formats.  What is wrong?  The program is updated, my drivers are updated.  I don't know what else to do!  I've been  on this for a week and I'm going to give up and not use this program anymore!  I would love a magic answer from anyone out there.  Thanks!