Make sure TV is not muted.Make sure the TV is not set to SAP (secondary audio protocol)
Make sure TV input is correct (someone may have accidentally pressed the "aux" input button or similar causing the TV to use an input with no sound going to it)
Make sure there is not a pair of headphones connected to the TV audio out jack on the side or front of your TV.Check all of the cables that are connected into the back of your TV. (it is possible the TV was moved slightly and a cable has become disconnected or loose)If you have a receiver or surround sound connected to your TV, turn it on and see if you get sound coming from the external speakers.Turn off the TV, cable box, and anything else connected to the TV. Sometimes turning everything off and then back on can fix the problem.If using an "S" video cable into an input on the back of your TV, these cables carry no sound, just video, so make sure you connect an audio cable too.Hook up an external device to the "TV audio out" input. This will be the test to see if it is a TV circuit board malfunction or the speakers are faulty in your TV.If you are connected to a satellite box, use the included remote and go into the "menu". Check to make sure sound settings are set correctly.
Read More: http://removeandreplace.com/2013/11/14/10-ways-fix-tv-picture-sound/#ixzz3lTeW6isH