If software is not the issue, you may have to replace the entire screen assembly. Don't fret yet, though, as there are some things you can try before resorting to the 'Nuclear Option'.
Try cleaning the contacts between the display assembly and the motherboard. Laptops are prone to collecting massive amounts of gunk and dust over time, and swabbing the connection with liberal alcohol ''may'' fix it. Remember to dry all components before reassembling the laptop.
If that doesn't work, there are other possible causes of failure. This includes power supply issues, motherboard issues, and graphics manager issues. If your computer supports it, you may be able to run an ePSA. This boots your computer into a mode where it systematically runs onboard tools to determine what may be broken. Different computers has different ways to access this mode, but you might be able to access it through booting into the BIOS mode.