Please do try these troubleshooting steps that may help.
- First is to do a hard reboot, unplug the AC adapter then press and hold the power button for 20 seconds then try booting it up again.
- If it will still load into a blank black screen connect an external monitor and see if you'll get any display from it. If there's a display on the external monitor that could mean that the problem lies in the built in display. If you can, open the laptop and check the ribbon cable that connects the LCD to the motherboard.
- If there's still no display on the external monitor you'll need to reseat the RAMs', turn the laptop completely off and unplug it from its AC adapter then remove all the RAM's off then put them back in making sure everything is seated properly.
- Here's a video on how to remove the RAM's. (Not in English but you should see how to disassemble it. )
- If reseating the RAM's will not work then the problem is the motherboard.