If users are able to watch a video, but there is no sound, it’s important to determine whether the problem is specific to QuickHelp, or is a more widespread problem. Please read this tech note to learn how best to make this determination. If the problem is not specific to QuickHelp, there is a good chance that the audio has been turned off in the browser settings. In IE, this is enabled by opening Internet Options > Advanced > Multimedia > Play sounds in webpages.
If this does not resolve the problem, please enter a ticket here