Windows Media Player Restoring Deleted Frames After Rendering The File

I cannot tell you how frustrating this is. I put a bunch of movie clips together to make a music video, and playing this video back in the Movie Maker preview reveals no extra frames or shoddy transitions, but after I save the project as a video and play it in a regular media player, frames that I had deleted show up in between transitions, no matter how many times I delete the frames or no matter how many frames I delete between transitions. They always come back and my music video is looking terrible because of this seemingly unfixable issue. So if possible I would like to know what I could do to fix this.