My laptop is HP6520s - KF081PA, came from seller with NO driver CD, have free DOS

When I use key buttons "Fn"+"F7"/"F8" to adjust screen back light to save power in Windows XP, there is no change to the light, after reboot, the back light is adjusted

However, when my laptop start up, I can change and can see it changing. So I think that there is some thing with Windows XP or I have to install some driver. (My WinXP is SP3 version 2002 - OEM)

I searched in Internet and someone said that I have to install HP Quick Launch. However, after install HP Quick Launch, the system hang up and I had to spend a day to reinstall WinXp and recover lost data.

That issue don't cause much trouble however, I'm not satisfy with it

Anyone can help me?, thanks alot

OK try this
go to www.hp.com
support and driver
click (Download drivers and software (and firmware))

then on the right side click auto detect
when fineched detecting click your OS then download the keybord driver

Thank Loay for your suggestion, however, there are 2 things that I concern:

1: I couldn't find "auto detect" to click, so I had to enter my PC model and chose the OS

2: There are only 3 driver for kb and mouse, 2 are HP Quick launch which I had installed and caused my PC to hung up and cannot use kb and touch pad

I still try to find the solution, did you have the same trouble as me?

Anyway, thank a lots

So now I'm still living with that annoying thing, who can relieve me?

just forget it and free my mind

how??
the auto detect is there (i just check it now its there)
if you can not fined it i will print my screen for you to show you where is it in HP website

http://www.hp.com/#Support
As you see on that page, there is no auto detect to click, just step 1 "Download drivers and software (and firmware)" and step 2 "Enter a product name / number"

I want to send you the captured screen of the website hp.com, however, I don't know how to attach file

in step 2
yes it ask you for prodect number but on the the right it say (Or automatically detect products)
with the button (start detecton) just click it

Unfortunately, I could not find the button like you said, so there is something that different between your PC and mine. However, I think that there will be the same drivers regardless what we did in step 2, automatically or manually. Unless I specify the wrong product code (99% that I did right - from the label at the bottom of the laptop). I install HP Quick launch and that software made my PC hang up when I try to use the build in kb and touchpad. Also, even when I use external kb and mouse to use that software, there is no button configuration for screen back light, only for functions such as volume up/down...

By the way, I think that my laptop has some compromise, I cannot turn on/off touchpad function when typing in documents because it has no button assign to this function. (Though it can be done by enable/disable the hardware-I thought)

Thank you for your supports

one funny thing: right after installing new OS (windows xp sp3), I can change the screen brightness but after installing some hardware driver, the above function disappeared:(