I have a Dell Precision M4600 laptop and it runs great I have all of the drivers installed, yet it won't allow me to control the brightness once I get into windows through the keyboard (Up until Windows boots it allows me to do so) I'm running Windows 10 Pro
It also interestingly will not do anything when I attempt to turn on the backlighting for the keyboard using the FN and then the right arrow key that is marked to turn it on. The BIOS allows me to predefine the brightness for whether or not it is plugged into battery or charger, and yet I can't adjust this while I'm in windows but it does display the brightness as "Changing" in Windows.
It also interestingly will not do anything when I attempt to turn on the backlighting for the keyboard using the FN and then the right arrow key that is marked to turn it on. The BIOS allows me to predefine the brightness for whether or not it is plugged into battery or charger, and yet I can't adjust this while I'm in windows but it does display the brightness as "Changing" in Windows.