Vista - Movie Maker Transition causes crash

Hello, I am trying to make very simple movies with Movie Maker that came with
Windows Vista. I can create a movie in the time line just fine. However, if
I go to Storyboard and try to add Transitions, my computer completely shuts
down. I am extremely computer illeterate, and I can't get Microsoft to help
without paying a bunch of money. Is there anything I can do on my own.
(Please write like I am totally ignorant because I am in this area) From
some of the things I have read, I am assuming it might have something to do
with codecs, which I really don't know anything about. Please help!
--
Susan