Brightness on laptop doesn't work at all

Question

I have an ASUS k72dr laptop. It's hard drive died, so I bought a new one. After installing Windows only available screen resolution was 800x600, obviously because of lack of proper video card driver.

And here it where problems started. I tried a bunch of different versions of video drivers, starting from latest AMD Catalyst to oldest AMD Catalyst versions and so on.

The problem is, after displaying Windows logo laptop's monitor turns black. I thought it is completely disabled, but now I realize that laptop's screen light just doesn't work. If I point a bright light to a monitor, I can see that in fact Windows is running correctly, I can open windows, see properties etc. But brightness is on the super low, I'd say lowest, possible level.

I tried changing laptop brightness via Windows built-in slider, but it doesen't affect anything.

If I reboot in safe mode, display works fine. If I then delete video card driver and reboot in normal mode, screen works as well but resolution is 800x600 because the lack of video driver.

Please advice me something about this situation

Answer 1

There is a common issue with AMD graphics card drivers not allowing notebooks to change screen brightness with the following fix:

1. Go to the registry editor (start > regedit)
2. Change both of the following registries to 0

KMD_EnableBrightnessInterface2

MD_EnableBrightnesslf2

The registry path can vary slightly, but it will be one of the following or something similar. To find they key, I did a search through the registry.

HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class{4d36e968-e325-11ce-bfc1-08002be10318}\0000

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class{4d36e968-e325-11ce-bfc1-08002be10318}\0001

3. Reboot.
4. If it still doesn’t work, in Device Manager, disable your video adapter and re-enable. Make sure your PnP monitor is still enabled.

Note: In my case MD_EnableBrightnesslf2 didn’t exist. In this case just changing KMD_EnableBrightnessInterface2 to 0 will fix the problem.

Source: https://community.amd.com/thread/184510

Answer 2

I think you're messing up with Drivers.

My suggestion is to boot up in Safe Mode and make a Driver Clean with some utilities like this.

Then reboot on normal mode, it should work but in low resolution mode.

If you have Win>8 it'll download the driver by itself and adjust the settings. Otherwise I suggest to go first with the graphics drivers provided by the manufacturer (Asus) on its website.