I am sorry to hear that have issues with screen brightness.
As far as I understand the computer comes with some power settings that when you unplug the computer, it will dim the screen automatically, this is a power saver feature from the computer.
If you are running the latest video drivers version 3345, there is an option for brightness control on all colors. This is available at Display>>Color>> Color Enhancement.
The other option is to create custom power plan, this will be through power settings within your operating system Control Panel.
Link to download latest video drivers:
Please filter by operating system version and try to install the driver when it finishes downloading, to verify that your system will accept it.
Thank you for your reply; however, this does not address the issue at all.
The screen dimming has nothing to do with the standard power and brightness settings. It occurs at any time when the the computer is running on battery power, not only when the computer switches from AC to battery, and the screen both BRIGHTENS and DIMS on its own but ONLY if it is running on battery.
This is an issue with Intel drivers (I have 3345). I do not experience this problem if I uninstall the Intel drivers and use the generic PnP drivers.