Changing Display brightness impossible

Hi@all

I am experiencing very annoying problem.
I am not able any longer to change the brigntness of the display via the known keys if the light sensor is deactivated.
If the light sensor is activated I can adjust the brightness but I do not like the sensor.

I can change the brightness without the sensor when I am in the BIOS and during windows is booting.

My system: Precision M4500 with Windows 7 Professional X64

PS. to make it not too easy the problem already occours when I just insert the Windows DVD and boot from it in order to reinstall Windows.
The problem also occours with a fresh and pure Windows 7 Installation.

Anybody?

Thanks in advance

 

Did you look at the relevant options in the BIOS?

John

 

Yes of course.
There are only two relevant Options under Video - I think

1st where I can Activate/Deactivate the ambient light sensor
2nd the default brightness for battery and normal power

And of course I already loaded the default settings and I went from Bioa A01 to A02 and back to A01.

 

Well solved on my own. once again Dell Tech had absolutely no glue on Friday.
After installing the display driver (180 or 190 series - NOT 250 series) you have to install the "security device driver pack"
I do not know why.

 

I was just going to suggest making sure you use the drivers provided on Dell's support pages.