No Sound

There is no sound.

I see no clue that there is a problem. However, when I select the Advance Volume Controls option on the top left panel in the 'Sounds, Speech, and Audio Devices' I get the following message.

There are no active mixer devices available. To install mixer devices, go to Control Panel, click Printers and other Hardware, and than click Add Hardware.

I only see 3 devices that are not installed.