Connect an external monitor to the laptop and see if there is a display showing on it.
If there is also no display on the external monitor then there is a problem with the GPU (or the CPU as often the GPU is integrated with the CPU) or the motherboard.
If there is a display showing on the external monitor then there could be a problem with either the video cable between the LCD display and the motherboard, the video cable connections (at either end - motherboard or LCD display), the lid switch or the LCD panel itself.
With the laptop turned on, shine a torch at an angle, close to the screen and see if you can detect an image on the screen at all.
If there is a display (and it will be very faint) then you have a backlight problem. Try it in a darkened room. This can be caused by either a faulty backlight power supply, a faulty backlight cable between the motherboard and the LCD display (it may be part of the video cable -not sure about this for your model), a faulty lid switch or a faulty LCD panel.
Hopefully this is of some help.