Hello Barrie Sambrook,
I understand you are having problem with using our driver in your Dell system.
Based on your description, your system has switchable graphics. This is means it has the Intel® HD Graphic controller and the Nvidia video card.
Since this is a special configuration, your system needs special software and drivers. I am afraid to tell that the drivers for this specific system need to be provided by the system manufacturer. We offer generic drivers for your system but as mentioned before, your computer requires special driver.
Since you have tested the latest generic drivers from our side, you may try another generic driver version from our side by accessing to the following link:
The other option would be to wait until the manufacturer of the computer release a driver for your system.
I went back to Dell and they were able to solve the issue with a new driver.
Intel HD Graphics 4000 and Windows 10 & Windows 8.1 ( Brightness fix with latest driver)
Brightness Fix with Driver Date 8/17/2015 )
Brightness problem Solved
Intel HD Graphics 4000 with NVIDIA® GeForce® GT650M graphics.
Intel HD Graphics 4000 Driver, Driver Date: 8/17/2015
Driver Version: 10.18.10.4276
Make sure you backup your registry first before proceeding!!!!
open regedit in Run Command
Registry has wrong value:
Currently reads as :
"Edit DWORD 32 bit"= f000
Registry with New Value:
You needed to change the value in registry to: ( f008 )
"Edit DWORD 32 bit"= f008
Then Restart Computer
Brightness Fixed with Latest driver.
Let me know if this was helpful to you