Please do try these troubleshooting steps that may help in solving the issue.
- Start by doing a hard reboot, remove the battery and unplug its AC adapter then press and hold the power button for 20 seconds then try booting it up again.
- Next to try is to connect an external monitor while the laptop is on and see if you'll get a display from it.
- If it doesn't work try to disconnect the ribbon cable off the LCD then connect it again to an external monitor and see if you'll get a display.
- Do also try to reseat the RAM's, remove them all for couple of seconds then put them back in making sure everything is seated properly.
- If all these will not work then the problem may not be the LCD but the GPU itself.