No sound on all sources? Be sure you check all inputs (am/f.m., internet radio, hdmi sources, etc...)
If all sources fail and there is no sound, try a factory reset. Hold the"Straight" and "start" buttons, you should see the menu, then shut it off. If that fails, try a firmware update. (It needs to be online ofcourse). Go thru the menu and it will let you know if it has the latest firmware. Good luck