The sound can be controlled from different devices.  Your workstation's sound is connected to a drop in the wall which then connects to a device in your sound cabinet.  In order for your sound to work volume on your workstation must be set to your desired level.  The device in your sound cabinet must also be powered on and the "Computer" knob adjusted to your desired volume level. 

If the speaker icon in your task bar has a red "X" on it then there is an issue with the drivers.  Please submit a ticket to resolve this issue. 

If it has a red circle with a line across it, then the volume is muted.  Right click on the speaker and select "Volume control" and un-mute the volume by un-checking the boxes that are checked.  Verify "Mute All" is not checked.