My Sharp, has no sound

I hit the mute button on my Sharp. When I hit mute again to return volume, it didn't come back. I'm connected to a Direct TV box. I was using the Direct TV remote at the time that's programmed to work with the Sharp/Direct TV box. There is a very subtle light "buzzing" sound, very discreet, when mute is off. When mute is on, the sound goes away completely. I've tried unplugging the TV for a while, but, that didn't work.

Any help would be appreciated.