Movie Maker uploads clips but theyre only 7 seconds long?

Hi There, Hoping someone can help me? My Movie maker has suddenly started doing something odd and I cant figure out how to solve the problem. It previously worked fine now all of a sudden when I try to upload clips it says they are only 7 seconds long and it wont play them. I tried uninstalling movie maker on my laptop and then re-installing it from the download on the microsoft site, but its still doing the same thing, anyone else had the same problem or know how to fix it? and if I cannot get it fixed, what is the next best, and most similar movie editing free software I can download to use if my movie maker wont work? thanks in advance