As a geek who realises that the average TV is just a computer with a tuner and a screen I began thinking "It's crashed" and my first geek instinct was "Reset it". Now that should be simple you would think? Nope.
  I needed to make sure that the hardware was fully reset. The only reset option I could find was to reset the picture settings. I pressed all sorts of combinations of buttons and no luck. I started googling, not much there but user manuals, that I had to pay for lol. I suddenly remembered that most TV's have a service menu where you could calibrate the colours on a more accurate level. Perhaps I can reset in that!
  Further googling found a youtube video showing me how to get into the service menu. I had to put the TV in standby and (this will work on Sony Bravia LCD TV's where the model number starts KDL)
- Put the TV in standby using the remote
- Press on the remote the following buttons: [i+], [5] , [VOL+], [ANALOG TV]
- After a sec a green menu should appear. BE CAREFULL IN TV SERVICE MENUS. You really really can bugger the thing up here.
- Now press 0 and 8
- The TV should reset.
Which it did. :-)
    That fixed the sound for the inputs :-) But the digital tuner still wont work. Looks like it blew and that caused the crash. Good thing the DVD recorder can be used as a tuner!
  Thankyou to the poster of this video:
www.youtube.com/watch?v=1J6w8cHRKu0