Windows Movie Maker KEEPS freezing/not responding?

Yeah, too many imported clips may be the reason. My Windows Movie Maker does that too. And I have tons of imported clips. Sometimes it won't even unfreeze after a few minutes like yours does. I'd lose all my work, and have to start all over. My friend's movie maker does that, too. And apparently, what we all have in common is alot of clips. Maybe you should just delete the ones you don't need and see if it works. Hope my bad experience with WMM helps :)