After working on a Movie Maker project over the course of several days, the clips in the preview window disappeared.  Previously had little to no issues opening and saving the project.  When I open the Movie Maker project file, I can still view the video in the preview window, but can no longer see the clips therefore I cannot continue to edit.

• I checked the source clips and they are fine.
• I uninstalled MM and then reinstalled, to no avail.  

This was a rather signifincant project (40 minutes worth of edited video).

Please help!  Thanks!!