On the
Windows XP: Movie Maker website, it says that Windows Movie Maker can be updated using
automatic update or
Windows Update. So see if there are any updates for it first.
If not, you can download Windows Movie Maker 2.0 from
ZDNet UK and reinstall it.
Or you can try a different program. I tried
searching for 'movie maker' on Download.com and there's some useful programs there.
/ 
