I have been editing a film on windows movie maker for a while and it has now stopped showing me the videos.

I can see the clips and audio in my timeline but it won't play. I need to sort this out asap as i have a deadline for this video. I have tried lots of methods i have read but none have worked yet. Also, when attempting to publish my video, it says 'Windows Movie Maker cannot publish the movie to the specified location. Verify that the original source files used in your movie are still available, that the publishing location is still available, that there is enough free disk space available, and then try again.'

This is really annoying me and i need some help to sort it. My laptop is Windows 7 if that helps.

Many Thanks.