screen brightness doesn't dim nor does light up screen,any help?

[paparazzo79]

Since I reinstalled Win 7 Ultimate and drivers for display card and Intel HD 3000 graphics screen brightness option doesn't work.
I mean it shows in settings, the silder goes left and right but it doesn't dim nor it does light up screen.
Screen is full lighted up.
I installed most recent drivers for ATI card and Intel HD Graphics.
I tried via Fn buttons same thing happens,I get notification,but no changes at the screen.
I doubt that it's hardware failure.
Is there something that I can do,to make this work,because I don't want to reinstall OS?
The notebook is HP Envy 17-3080ez.
Ot if there is any alternative software for free to change screen brightness.
I tried DimScreen but it only dims screen and I don't like it.

 

[wither 2]

I found a long winded thread on this issue and the following was the most simple solution (may not work for everyone)-

"Open the registry editor (regedit.exe) and find the FeatureTestControl value. Mine was located here: HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\Class\{4d36e968-e325-11ce-bfc1-08002be10318}\0000
- Note the original value just in case you need to set it back (my original value was 0000f000)
- Set it to 0000ffff (if this doesn't work, try 0000f940)
- Reboot"

I would either save the registry or that particular HKEY before making any changes.