Hi,
Try connecting an external monitor and check if its' display is OK.
I''f it is also showing no display'' then you have either a GPU or motherboard problem.
''If it is showing a display'' then you have either a faulty video cable, faulty video cable connections at either end(motherboard or screen), a faulty lid switch, a faulty backlight power supply or a faulty LCD screen.
To test if it is a backlighting problem try shining a torch at an angle close to the laptop screen and see if you can detect an image at all. Be aware that it will be faint.
''If you cannot see an image'' at all then you have either a faulty video cable, faulty video cable connections at either end(motherboard or screen) or a faulty LCD screen.
''If you can see an image'' then you may have a faulty lid switch, faulty video cable or a faulty LCD screen.