I alerted your post so an Apple expert will reply soon.
I attached an HDMI cable from y macbook to my LG42" tv (at the moment the tv is in France and I don't know the model number - it's about four years old) and it worked perfectly. However I forget to keep the macbook on charge and it ran out of battery and the screen then went black. When I attached the power cord to the computer the TV picture was only of the desktop picture (no icons) - when I used the macbook to select and play a film nothing happened - just the desktop picture. This was the same with either HDMI TV ports. I assumed the power shortage has damaged the cable but when I returned to the UK and connected the macbook to my sanyo TV via HDMI it worked perfectly.
Is it possible the the power cut off with HDMI cable connected blew something out on the TV so that it could no longer receive video and sound or icons but only the static desktop picture?
I powered the tv off, reinserted cable etc but the problem remained.
It works fine with my other TV so it must be the LG.
Any advice most gratefully received.