I recorded a seminar for my office, and I'm trying to edit out the front and end parts of it because we start the recording before the seminar actually starts. 

I split the front section I don't want, and then remove it - gone completely from the movie maker. And after I save the video, if I open the video, the visual part of the recording skips in a fast-forward mode to 34 minutes in, while the audio stays fine. The problem is, the visual is all the slides that go along with the talk. 

What's happening that it's skipping like this visually? And how can I fix it?