How to disable auto-brightness in Windows 8.1 x64?

Question

Windows

Hello,
Brightness jumps in Chrome, Mozilla, Explorer browsers, when watching movies and in games everything is fine.
Can you tell me what to do with auto-brightness in Windows 8.1?
I can’t cope with it in any way, I switch from a “light” site to a site where darker colors predominate - the brightness gradually darkens, and then when I switch back to a “light” site where light design prevails, the brightness starts to gradually increase and reaches the optimal one, as since this very transition from a "dark" to a "light" site and back hits the eyes very hard.
I have already tried to set the brightness in the low backlight mode. And the power consumption settings to the maximum, the same thing, it worked for one day - the brightness did not jump, and then it seemed to go astray again, and the automatic brightness adjustment continues to work.
I don’t know what to think anymore, what’s the matter either in the G8 or in the IPS screen ...
The computer parameters are as follows:
Laptop Dell Alienware 17 R3
Proc: Intel Core I7-6700 HQ 2.6 GHZ
RAM: 2 x SO-DIMM DDR4-2133 ( 8GB + 4GB) - 12GB
Video: Intel HD Graphics 530 1GB & NVIDIA GeForce GTX 970M 3GB
Windows: Windows 8.1 x64
Screen: 17.3 inches FullHD - IPS matrix
Software: firewood is all native factory, did not update anything
Tell me how to turn off this automatic brightness control. I would like to leave the screen brightness at the same level so that it does not jump depending on the brightness of a particular site.
Thanks in advance!

Answer 1

https://www.google.ru/search?q=windows%208%20turn%...
or in Russian
https://goo.gl/kYiOVW