You can adjust the sound in the viewer by using the volume control button at the bottom of the presentation where you see the speaker icon. Other than that, if you already have the master volume on your lap top turned all the way up, you may want to also check the mixer settings to make sure that the volume setting for the Veritas Prep On Demand is turned up as well. You can get here by clicking on the speaker icon on the bottom right corner of your task bar and clicking on "mixer". You will see volume settings for several applications there.
Best of luck!