I changed my .mov file to a .avi file with a website and Windows Movie Maker still won't support the file.

AVI files are tricky. It isn’t really a format, it is a wrapper. What is inside could be a lot of different video and audio types.

My advice is to convert to mp4 if you can. That is a pretty universal codec. Anyone with Quicktime and iTunes will be able to play it. And the quality is good.

This is another way around your problem. You can play .mov file with quicktime player (of apple). There are other players that might also do the job, here are some: vlc player, gom player, etc.
If, somehow, you want to convert to some other format, you can look for “total video converter”.
You can download some of these from: http://www.9down.com
Or otherwise, try searching it on google.
Hope this would help.