Re: Quickest way to add titles to video files?
If you're files are mismatched, they won't splice together well. The audio is important since that's your sound. File type will determine the final quality and, thinking about it, I'm pretty sure Movie Maker has weirdness in regards to format. A program like Premier, and Audition to clean up your audio track issues, would be ideal, but it's not quick if you don't know what you're doing.
Someone once gave me a Movie Maker file to clean up. I couldn't get it to open properly in a real editing program. Unless the entire project came from MM, don't bother using it.