Can't play the video from lesson page

I have just set up a test account for my first workshop session tomorrow. I can’t play the video from within the lesson: apparently wmp doesn’t do this form of MPEG-4 File.

I had no trouble watching it when Steve posted it first in the forum.

As I don’t want a non-functioning video when I am with prospective new members I need help, please. What do I need to do?

Well, I have just installed QuickTime onto my notebook. It did the trick. Now to tackle my fairly old computer…