You can do what you want with version of PPT later than Off98. Here's how: (Note, these steps may differ slightly in PPT2K - I'm giving you the PPTXP steps.

1. Open your presentation.

2. On the Insert menu, point to Movies And Sounds, and then click Sound From Gallery, Sound From File, Play CD Audio Track, or Record Sound.

3. After you insert the media (sound), select the media object, and then right-click Custom Animation

4. In the Custom Animation pane/dialog box, right-click the sound object and select the Timing option

5. Click the Effect tab on the dialog box that appears

6. Choose the Start Playing option "From Beginning"

7. Choose the Stop Playing option "After X Slides" - replace the X with the number of slides in your presentation

8. Click OK

James