Your laptop's LCD panel or internal cable is likely damaged.

Once in Safe Mode, you can use to uninstall or update your display drivers . 6. The "Emergency Reset" Pinhole

Your screen may blink or beep as Windows resets the display driver. If the screen comes back on, you’re good to go. 2. Perform a Hard Reset

If your screen works for a moment when you turn it on (showing the Lenovo logo) but then goes black, it's likely a Windows or driver issue.

To determine if the problem is your screen or the laptop's internal "brain," connect to an external monitor or TV via HDMI.

Did your screen before it finally went dark?