In Windows 7 Movie Maker, a clip in a movie i'm making won't play.?

I'm making a clip montage for a Facing History project, and I'm having a bit of trouble. Most of the clips I'm using are short, but there's this one 4 minute clip from Harold and Kumar Go to Guantanamo Bay (The g soda scene, it's on racism :P) that's about 100 MB somehow won't play when I preview it. It eventually plays, but it takes too long and all the other scenes play quick as hell. I already added most of the clips to the montage, including the harold and kumar one, but that's the only one that only shows a black screen when playing through it. Is there any way to fix it?