Try downloading a converter for the MP4 file and convert it to like a WMA so you can use movie Maker in Vista. I'm pretty sure you can use Movie Maker to cut frames out of a video because I know in Windows XP you can do it. I'm sure Movie Maker is not much different in Vista (features wise),
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My AS has its Up and Downs, But I think that it's for the better. The world would be a less interesting place without me and my AS.