You have a problem with the backlight inverter board.
http://www.ebay.co.uk/itm/4H-V0708-001-E5-INVERTER-PANEL-INV-05-/150786271236?pt=UK_Sound_Vision_Other&hash=item231b8fe804
If you take a flashlight and shine it on the screen, you should see some kind of a picture or movement.Replace both boards.
flyatyou66, June 2014