Dell LED laptop screen replacement: brightness controls
After replacing the LED screen in your DELL laptop, you may find the brightness controls no longer function. Pressing the brightness up and brightness down on the keyboard has no affect on the display brightness. You may also find that when running on battery power the display is not dimmed; therefore the battery life whilst not using the mains power will be considerably shortened.
The problem in detail
You’re not alone this problem Is being reported everywhere http://www.google.co.uk/#hl=en&q=Windows+7+Laptop+Brightness+Control+Problem&aq=f&aqi=&aql=&oq=Windows+7+Laptop+Brightness+Control+Problem&gs_rfai=&fp=1&bav=on.2,or.r_gc.r_pw.,cf.osb&cad=b
You can try updating the following:
Update your DELL Graphics Drivers at DELL Support
Update the DELL System BIOS at DELL Support
Install the Latest Dell QuickSet: Win7 32-bit Win7 64-bit
If this solution does not work for you, try the neat Freeware stand-alone brightness control called Desktop Lighter
It runs unnoticed in the system tray, uses only 1.5mb RAM, launches with Windows and uses Ctrl+> and Ctrl+< keys to control the brightness rather than the Fn keys.
17.3" DELL systems including the DELL 17, XPS 17, Studio 17, 1700 series, 1731, 1740, 1749 and other models that are fitted with HD resolution 17.3 inch LED screens.