The good news is that the TV is not broke and can be fixed. You will first need to check for any cracks on the front screen of the TV. If there are any cracks then you will need to replace the screen itself, which ranges from $100 for smaller sized TV's to $500 for larger sizes. You should probably call a local repair shop and ask them for a quote. If there are no cracks then the problem may be from within the TV. If this is the case, then you will need to figure out what part of the LCD is broken. It may be either the LED lights or CCDL's (cold cathode fluorescent lamps) that are broken. You should take it into a repair shop and let them fix it, because messing with the LED's or CCDL's is very dangerous and should only be done by a professional. The LED's should cost $100 tops to replace and the CCDL's should cost about the same. Hope this helps!
Usually answered in minutes!