It seems that this problems affects various brands of laptops and ultrabooks that have dual graphics adapters – Intel and some dedicated chip: after some time you cannot control the brightness of the display. Not with the function keys, not through Windows 8’s and Windows 7’s software controls and not by going to Power Plan’s settings.
After trying to uninstall the graphics adapter drivers, reverting to Windows Update drivers with no effect, we found this post that recommends uninstalling the Monitor in Device Manager. And it worked!
- Go to Device Manager
- Expand Monitors
- Right click your monitor (Generic PnP Monitor in some cases)
- Click Uninstall and check to remove driver files from system.
- Scan for hardware changes