Other things to check, aside from the Prefs file:
The Normal template (in ~:Apps: Office: Templates)
The Word Font cache
The Carbon Registration Database
With Word quit, trash or rename, all will be automatically recreated when
Word launches again. For the Normal template and the Prefs file, you want
to RENAME rather than trash them, as they hold customizations. If the
problem persists with a new Prefs file, you can just delete the new one and
rename the old one back to the standard name. With Normal, even if the
problem stops and Normal appears to have caused it, you can copy many of
your old customizations into the new Normal via the Organizer in Word. The
Font cache and Carbon Registration Database can just be deleted.
You should also check if you have any add-ins in the Word Startup Folder
that may be causing conflicts--remove them all and replace one by one.
Andrew, if Word is crashing on opening, the problem may be fonts. This link
includes a link to the procedure for that:
http://word.mvps.org/FAQs/WordMac/WordXTroubleshooting.htm
(but you can't view it in Safari, sorry) The page will also lead you to
detailed instructions for the procedures above.
DM