I can't change laptop screen brightness in any way - by buttons Fn+F7/F8 or through the driver. Other Fn buttons (ex. Fn+F3 => WWW) work correctly (HP Quick Launch Buttons installed successfully). This trouble is observed only in Windows XP. In Windows 7 the buttons Fn+F7/F8 change brightness.
All other drivers were installed correctly. I think it is problem of Intel Graphics Driver for Windows XP.
System info: - HP Pavilion dv6-1354us - Windows XP Professional Service Pack 3(5.1.2600) - Graphics driver: Mobile Intel® GM45 Express Chipset - Graphics driver Version: 126.96.36.19948 - Accelerator in Use: Mobile Intel(R) 4 Series Express Chipset Family - Video BIOS: 1706.0 - Current Graphics Mode: 1366 by 768