Not sure quite what you mean when you say I also disconnected the flex from the LCD and the motherboard and nothing happened. Did you mean that you disconnected and then reconnected the flex cable and the display still exhibited the same problem?
Try connecting an external monitor to the laptop and see if its' display is normal.
If it is the same as the LCD screen then there is a problem with the GPU or the motherboard.
If the external monitor's display is normal then there is a problem with either the video cable, video cable connections at either end or the LCD screen.
As you have removed/reinserted? the video cable then the problem is most likely a faulty LCD screen.
Here is a link to the service manual for your laptop. Scroll to p.69-70 to view the necessary pre-requisites and then the procedure to remove the LCD module. Then scroll to p.94 item #1 to view the part number(s) for the LCD module. Once you have determined the correct part number for your particular model variant (the number should also be printed on the back of the LCD screen in your laptop) search online using just the part number only to find suppliers of the part.
Hopefully this is of some help.