Does Your S90 Have Sound On Video Playback?

Problem solved before I got a response. I would have deleted this post, but I don't see how.

Yes, it does. The speaker is behind the four little holes right above the Playback button on the back of the camera. (on the back, just to the right of the ridge/thumb grip below the top mode dial)

Perhaps you just need to turn the volume up? Pressing up and down on the ring during playback adjusts the volume. (there is a little volume level meter all the way to the right, next to the scissors icon)