Video clips play on screen but show as blank when using projector

[Guest]

I'm inserting .mpeg and .avi clips into my presentation which play perfectly
on my laptop screen but show as blank on the accompanying digital projection.
If I play the clips outside of Power Point using Quick Time they do show
correctly on the projection. Quick Time only however, both Windows Media and
Real Player show blank area where video should be. I'm trying to simulate a
TV broadcast and it really destroys the flow of the presentation to stop,
call up the Quick Time player (which is then visible) using action button, go
to full screen and then go back again to presentation. Any suggestions?
Thanks for the help.

 

[Echo S]

I'd toggle the display so that it plays only on the projector, and not on
both the projector and the laptop. That's the only reliable way I know
around this one.

Videos play correctly on computer but not on projector (black box)
http://www.rdpslides.com/pptfaq/FAQ00467.htm