Win10 screen brightness can not be adjusted how to do

The problem is as follows:
• First, try to uninstall the discrete graphics driver in safe mode. The screen brightness can be adjusted freely after uninstalling;
• Second, check the device manager and find that the discrete graphics driver is not installed. The brightness is still not freely adjustable when it is installed again.
Try to solve the problem by:
• Right-click on the "Start Menu" - select "Run" - enter "regedit", press Enter to open the registry, and then expand:
{HKEY_LOCAL_MACHINESYSTEMControlSet001ControlClass{ 4d36e968-e325-11ce-bfc1-08002be10318}
• Change the KMD_EnableBrightnessInterface2 key value in 0000 and 0001 to 0.

another, if not the key, you can create a new, type DWORD. If there is no 0001, just modify the key value in 0000.
• Restart the device after the modification is complete, and then try to adjust the brightness.