Hi @quatar,
That’s a really good question! (sorry, out of points today – I’ll try to give you some karma tomorrow)
What version of Powerpoint are you targeting? Here’s a page about media formats for Powerpoint 2007, for which you could use one of the following formats:
In what format (container/codec) are your videos? You might not need to convert them if they’re already encoded using a codec that is available on the system you’re going to use for playback.
I’d suggest that you ask someone (a technical contact?) at the host organization to give you the specs of the system. Is there any way that you or someone else could do a test run of your presentation file through the host’s computer?