my classmates and i have been editing a short film for our school project for a week now. i was putting subtitles on the said film and whilst typing, windows movie maker stopped and closed on its own. when i tried opening it, there was  a display window that said my file might not be compatible or it might have been corrupted. how do i restore the file??????? WE NEED TO PASS THIS TOMORROW AND WE STILL HAVE TO RENDER THE MOVIE WHICH TAKES A VERY LONG TIME PLEASE HELP