Work on 5.3 meg file constantly cra****ng

Version: 2008
Operating System: Mac OS X 10.5 (Leopard)
Processor: intel

I've been creating and editing a file that came from the Windows version.
It has text and tables and that's about it. During editing, Word crashed
at least five times. It just ended suddenly with no error message other
than the re****t screen coming up.