Alice,
It sounds like you might be talking about a Powerpoint file with embedded audio. When you click on a link for a Powerpoint file in Canvas, it uses DocViewer to render the individual slides on the web page. But when it does this it can't play any special things such as media (audio and/or video). In order to access media like that you'll need to download the powerpoint file and open it on your computer using the PowerPoint application. Normally when viewing a powerpoint file in Canvas there will be a link directly above it you can use to download the file.
Rick
This discussion post is outdated and has been archived. Please use the Community question forums and official documentation for the most current and accurate information.