Hi,
The fall might have damaged a component inside the laptop. Here are some troubleshooting steps that I can suggest.
- Start by doing a hard reboot, remove the battery and unplug the AC adapter then press and hold the power button for 20 seconds then try it again.
- If the same problem will persist do a clean install of the graphics card driver.
- Go to Device Manager and uninstall the Nvidia graphics driver.
- Next is to open Programs and Features then uninstall anything related to Nvidia.
- Once completely uninstalled, download and install the latest driver.
- Here's the link: nvidia.com/Download/index.aspx
- Reboot the laptop once the latest driver has been installed.
- After the reboot, do set Nvidia as the default GPU.
- Here's how:
http/nvidia.custhelp.com/app/answers/detail/a_id/2615/~/how-do-i-customize-optimus-profiles-and-settings%3F
- If all these will not work do open the laptop and check the GPU is if it's seated properly, specially if it's removeable.
- Apply new thermal paste on the CPU and GPU as well.