Fixed: Dell laptop screen issue after Windows update
1. Press ON Button
2. When Screen Backlight turned on, spam F12 Button
F8 to get into Safe Mode has been disabled in Windows 10. You can enable it but it requires using BCEDIT to modify the boot process. Otherwise the standard way to get into Safe Mode is to hold the Shift key while pressing the Power > Restart button. When you get to the "Choose Options", select "Troubleshoot" > "Advanced options" > "Startup Settings" > "Enable Safe Mode", then reboot and select Safe Mode. Of course this does not help you if you cannot boot your system initially. In that case you need a bootable CD or flash drive containing a Windows 10 Recovery Drive or Windows 10 Installation media.