Just to jump in for the sake of clarifying, when you say you replaced the display cable, is that the display data cable or the inverter cable? If it's the display data cable, it shouldn't be responsible for a problem like this. Rather you would need to try replacing the [product|154115|inverter cable]. If you have already replaced the inverter cable, it sounds like the LCD panel is bad.
(yes i have read all the comments! I just wanted to clarify that one point)