You may have to install Powerpoint Viewer 1997 (ppview97.exe) as later versions may not support the Sound.  Click on the following 2 links one after the other to install.  If you have high speed you can Save to disk vs. Open. 

aaaaaa/ppview97.exe (save, install)

Mel's Tribute - PowerPoint Presentation (right-click, open, select from a list, choose Mel Sat.ppsx)

Note: If a slide appears without a picture, hit the spacebar once. (typical Microsoft bug)

Let me know if it works with sound for you please.

Carolyn's 40th - PowerPoint Presentation (choose Carolyn.ppsx)