Can I safely uninstall and then reinstall SP2 and/or SP3 on Windows XP?

The reason I ask is to determine if it would solve my Windows Movie Maker problem: preview pane (monitor) remains black despite dragging images onto the Timeline, and nothing can be saved to my computer.  There's an error message that the source no longer exists or there isn't enough disk space (there is plenty) and another thing which I've forgotten.  Someone kindly suggested Pstory, but I can't persuade it to work despite having studied the tutorials.  Pstory won't allow me to make a video more than a minute long despite a three minute soundtrack.  I've given up on it.  My guess is that the only option I have is to purchase a movie maker compatible with Windows XP if they exist.  If they do, what are they?  Thank you.
Sincerely,
Kestal Phillips