What file should I publish movies that I make in Windows Movie Maker to get the best quality (for making rs videos)

A while back, the words would be yellow and they would be clear quality, but now they are bad quality and the words are orange, and half the time the video cuts out earlier than it should, but the music will continue playing.

I'm pretty sure that it automatically saves it as a .wmv. Be sure you're choosing a good resolution (you can go on google and look up youtube resolution to see which ones best suite you).