Windows Movie Maker Problem

OK so my windows movie maker won't import videos anymore. whenever I try to import a video, it says "Windows Movie Maker has encountered a problem and needs to close." I havn't gotten a new camera and i have ran virus scans and my computer's clean. I've also downloaded Service Pack 3 and that didn't help. When I try to uninstall it, I can't find it in the programs list. I can't find the cd that has all the programs on it either... So... anyway...
Any help on fixing the problem and/or re-installing the program?