Tried everything checked the firmware update its not available i use the TV with HDMI and I am getting the same problem.
Now i am thinking that it might be a hardware issue some malfunction inside the TV...
What I meant to say was eventhough you are using HDMI, it should have some form of option in the menu to chose what type of HDMI it is. Such as Cable, DVD, BluRay, PC/Computer, etc.
I get that option on my Samsung ES7500 LED. If I rename my HDMI connection to PC DVI, or plain DVI, the TV turns off all extra video enhancement features and keeps it to basic.
Anyway I did a quick google search and it turns out that half screen issue is quiet common. Mostly people get half dead screen or lines on one side or completely incorrect colors etc. so it seems to me that this could be a sign of defect or hardware issue which can not be solved normally (I'm guessing you did a complete power cycle by disconnecting all wires on the TV and waited for 15 minutes until reconnecting).
Therefore I'd recommend you to sell it off - no need to repair it if you are not in warranty. Considering your problem isnt easily noticeable, you maybe able to find a buyer who is willing to live with it.
Buy a Samsung then