Trimming the end off of a project

I ave just finished a movie project but have one annoyance remaining. The
material I added (video+audio) should end at 6:20 but the project keeps
playing past until 10:54 and the stops. Everything after 6:20 is blank but I
can't select it and trim it. If I write it out as a movie file ie .wma I get
a file that is 10:54 long with nothing after 6:20 - just as it previews in
Movie Maker.

How can I trim this portion after 6:20 out?

One thing I can add is that I dragged audio tracks into the project that
were much longer than the original video content. However, I have trimmed
them to fade out and end early so there is no audio past the 6:20 point. I
can only guess there might be some artifact of the audio that has pushed the
time to 10:54

Thx