If you wish to get some details; visit the site linked here. Pull up older posts.
http://electronicshelponline.blogspot.com/
Line faults & possible causes to LCD & Plasma screen are given with illustrations. You can get an idea about the fault to an extent. Faults to all LCD & Plasma screen are similar, irrespective of its brand and screen size.
Something died in there - perhaps a capacitor or a solid state device just blowing and cracking into pieces. happens. Open up the set and see if you can spot it around the power supply area.