thank you for helping, here are the answers to your questions...
1. It is power point 2007
2. System I run is Windows XP 32 bit
3. Video is .avi

Here is my procedure
>insert
>click on movie arrow - opens small pull down and select - movie from file
>opens my folder where the power point and the movie files are stored
>Slect movie by double clicking on it
> Black box appears in my slide
Does not play in pptx or final slide show.

I look forward to your reply
thank you