Today, when turning on the Samsung LCD TV (approx. 3 years old) the audio was not working. It's a very basic connection with ATT UVerse cable connected from the wall to the cable box then cable box connected to TV via HDMI (via three cables as one cable runs thru the wall). Any ideas why the audio stopped working?
Unplug the cable box for 15 mins, plug it back in and try again.
The last part of your post confused me when you mentioned 3 cables. The only cable running from the box to your TV should be HDMI, it could be getting confused if you have additional RCA cables going into the TV from the box.
See if you can get sound from the TV when playing a DVD or something along those lines so that you can rule out the TV as a problem. If you have a spare HDMI cable try that one out. Otherwise call your cable company and see if they can reset the box and help you out.