I have an external monitor attached to my laptop. The hardware controls have stopped working (on the external one), and I would like to dim this monitor a bit. Every web page I've located for help, shows two separate monitors to select from in Windows 10, however, in my setup, it shows only one monitor, with a "1|2" in it. Consequently, the settings below operate on my laptop monitor. How can I select the external monitor and change the brightness setting?