If the screen is blank on the second monitor also, then it could be an issue with the video cable. Try replacing the video cable or using a different video cable if you have multiple connections options like DVI, HDMI, etc. If using VGA works, then it could mean there is an issue with your HDMI or DVI cable.
If the motherboard was damaged when you dropped the laptop, you may not see anything on the screen when the laptop is on or when you connect it to an external monitor. A [https://www.minitool.com/backup-tips/how-to-test-motherboard.html|damaged motherboard] isn't as simple to diagnose as other parts of a computer.