Windows Movie Maker Error: 0x80004003 and Error: 0x87160139

Hi!

I'm trying to create a simple movie (which I have done many times before on Windows Movie Maker) however recently it has developed an error.

This is what happens -

1. I open my wlmp file.
2. I wait as the images for the videos begin to appear randomly.
3. A message appears at the bottom left of the screen stating that "Movie Maker is Preparing Your Files," and a green loading bar moves along through all the videos.
4. Yellow triangles with exclamation marks gradually appear on every single video in the file.
5. When these videos are clicked, a message comes up saying "Do you want to remove "Filename.(mp4 or mov)" from the project? The file has become corrupted or in a format that Movie Maker doesn't recognize. This movie can't be saved or published until Filename.(mp4 or mov) is removed from the project.
6. The error name is either 0x80004003 or 0x87160139 depending on which video is clicked on.
7. When I try playing any of the videos, only a black screen shows on the playing screen. Any mp3 files which have been added as music however, still play, though without any visuals.

I have tried uninstalling and reinstalling the program, and the same problems still occur.

I know the files are not corrupted, as if I restart my computer, the problem is fixed, until the next time I open the project.

I know that the problem is not my video files at all, since I have always used mp4 files and mov files, and they have always worked

If anyone has any ideas, please reply as soon as possible.

Thanks!