Sorry if this is kind of stupid, but how do I change the google video format so that I can edit them?

I want to mix many videos together using Windows Movie maker but I need to change the video format. Thanks in advance.Sorry if this is kind of stupid, but how do I change the google video format so that I can edit them?You can use %26quot;ImTOO mpeg converter%26quot; to change to many types of video files.