Hi, just post for helping people who are annoyed by Inspiron 11z's screen illumination problem in XP. i found NEC's screen controller software could handle this issue quite easy. step by step guide as following:
1, go to microsoft skydrive,click the zipper document icon to download the .rar package:
2, unzip the archive, and put the .exe in systemic partion. run BrightnessController.exe . if ask for digital signature, allow it. it's just for certification purpose only.
3, adjust your screen illumination by click the small icon in system tray zone. do remember to add this software as "run in system boot up" if you wanna adjust it at any time.
Wish it would help and enjoy your 11z.