Windows Movie Maker Help needed!!

I’m trying to make a music video but my Movie Maker won’t allow me to import the video files I need, saying I don’t have the right codec installed. Can anybody help? Please?

What kind of file are you trying to import? The file extension would be very useful to know. If it’s an avi use gspot or avicodec to find which codec you need. If it’s a wmv, use avicodec.
http://www.headbands.com/gspot
http://avicodec.duby.info

i can upload my video but when i try to play it back i don’t get sound, what did i do wrong?

I am trying to import some mp4s I got from Itunes, and I also get the response about not having the codec.