What is a decent, free software for windows that i can make lyrics videos on?

so you know the people on youtube that create videos with song lyrics? ...like for example, you choose a song, and then make a whole video with it's lyrics. i did that with windows movie maker, and uploaded it to youtube and youtube said that the file wasnt uploaded because it was not in a convertable form or whatever. i guess youtube only accepts wma, mp3, etc. any help?