Advance PowerPoint slides automatically

"You may have an embedded sound file. If so, do this:

Go to the first slide where you have the sound file embeded
Select Animation
Select Custom Animation
Click on the Sound icon inside the slide
On the right side of the screen, click on the pull-down menu for the sound object
Select Effect Option
Under the “Stop Playing: After”, enter 99
Click OK

I don't know why it works but it works. It is the same solution for the previous version of Powerpoint."