It sounds more like PowerPoint is hanging rather than the Mac crashing...
When this happens can you Command+Tab to Finder & select Force Quit from the
Apple menu? If so that isn't a computer crash. That may sound 'picky' but
it's a very significant distinction.
If "has sent me" is meant to suggest as an attachment to email there are any
number of opportunities for maladies to be inflicted on the file. The best
protection is to have the sender attach Zipped files, save them to your HD &
open them from there.
There are still a number of other possible causes but my first guess is that
the files presenting the problem include links to external content such as
images, audio, or other media items which can't be found when the show is
run. If that's the case the sender needs to include the linked files & you
may need to re-link them locally. Otherwise you'll need to determine what
the links are & delete them in order to run the show.
It may also be that the files include embedded content which isn't supported
by the software or media players you have. It may even be content not
supported by OS X itself. In this case as well as the matter of links you'll
need to take an accurate inventory of what the file contains.
From a local viewpoint make sure you have Office fully updated (11.5.8 was
just released), that OS X is fully updated & repair disk permissions.
HTH |:>)
Bob Jones
[MVP] Office:Mac