Hello.  So I've been searching the forums and can't find a problem quite like mine:

So I am in the process of mashing some family videos together through Movie Maker.  I had about 20 minutes of video in the other day, saved and closed the project.  Now, this morning when I opened it back up - half the audio is missing!  It's strange because some of the videos have sound and some now don't!  When I place the settings to show waveforms, they are only on the videos with audio still in tact.

What happened?  Why would the audio stay on half the videos and not the other half?  And it's not cut down the middle - the videos are interspersed with which play audio still and which don't.  But they all used to play!  When I originally added them I could hear them all with no issues!

I have not moved their locations and get no error messages.  The audio is just gone from half! 

Please help.  I don't want to start over!

Thanks.