Hi,
Try connecting an external monitor to the laptop’s HDMI port (if it has one) and check if there is a display being shown on it.
Even a TV can be used as an external monitor as long as it has HDMI inputs and you have a HDMI cable which is compatible with both the TV and the laptop HDMI sockets. Don’t forget to change the TV “input” to the HDMI port that the cable is connected to.
After connecting the external monitor, turn on the laptop and then when it has booted up, press the F4 key to toggle (i.e. press > release > press > release etc) the video output between the laptop screen, both screens on together, one display across both screens (extended view) or external monitor only.
If there is no display on the external monitor either you have a faulty motherboard.
If there is a normal display on the external monitor, it may be either a faulty LVDS cable or cable connection at either end motherboard or display panel or a faulty display panel.
What is the full model number of the laptop?