ViewSonic VA1912wb Monitor "undo mute" Questions

...clock and open it up..volume mixer...make sure the lide is full on the top and not muted...if it is undo muted ...also check ur cable to ur pc..if it was working yesterday...well something gone wrong ...

...undo. Would appreciate help. all other volume controls within the computer are turned up. Thanks. I have the same problem but after much playing around with the monitor controls I found that ...