Power Point

I don’t know if this is an area you cover, but I need help with a Power Point Presentation.
I have put in a sound that I want to play through all 18 slides. When I view it within the program, it works just fine. But when I publish it to my site, the sound stops after the first slide. I have told it to continue playing for a large number of slides–greater than the 18, and told it to loop until stopped.
Help, if you can.