It just would not play! I followed all the instructions about inserting video. Including this one which is as clear as a bell.
The image appeared in the Powerpoint, yet still it would not play in presentation mode. Finally, after much googling, I found the answer – a simple one! Videos in PowerPoint are not embedded, merely linked to. The problem lies in the player that Powerpoint uses being able to follow a path to the file (which should, incidentally, be in the same folder as the PowerPoint presentation).
This player is limited to following a path of only a certain number of characters (a hundred and something, as I recall). My video and Powerpoint was so deep in the folder structure, and the video loop had such a long file name, that the path exceeded the allotted characters.
Solution? Easy-peasy-lemon-squeazy…when you know how! Simply shorten the name of the video loop file. I suppose I could have copied the whole shebang onto my desktop and relinked the videos from there.
So now, job done! Everything plays nicely when it should It even works in PowerPoint Viewer, when packaged for CD. All that is left is to get the background music syncing with the voiceover and we’ll be done.