I have a laptop (Lenovo) with an external monitor connected through HDMI.
It has Windows 11 24H2 and all worked fine. After an update, suddenly, the laptop's built-in monitor turn to black and nothing is displayed, but the external monitor is fine.
I noticed that when the laptop starts, the Lenovo logo is displayed, so I guessed that nothing is wrong with the hardware, so I looked for Windows settings.
I tried all kind of settings, searched through WEB, but nothing helped me.
By chance, I noticed that the brightness slider what dragged to 0. I drag the slider to 100, and, voila, the laptop's screen is back.
After that, further search including the keyword "brightness", revealed a related post from 2022 including another Lenovo laptop with a similar issue.
