How to fix adjust screen brightness issue in Windows 8/8.1
If you are installing Windows 8 in older systems that came before the release of Windows, you will face this issue.
When you install Windows 8.1 and try to increase or decrease brightness, nothing happens.
The display driver is not installed. The default “Microsoft Display Driver” is installed by default.
You need to find the driver for your motherboard/processor. I found driver for my processor from Intel Download Center. Check your windows version and search for the driver accordingly. Download the .exe file and run it. During the installation your screen will flicker multiple times and you will have the issue resolved.
Make sure you download the correct driver.