CQ40 have few version.The normal 1 is the Compaq CQ40-115AU.
Maybe Vista Ultmate is too much for your lappy.Is the DVD's ori or 'ahem' 1?

You can try search in garage sale section.There is 1 guy who is selling this lappy with RM5 for delivery charge.

Try calling the HP service centre.They will answer all your queston.

Just bought Compaq CQ40-115AU today.Installed win xp.But after installing all the drivers from page 1,still have 6 unknown driver.Anyone knows whats the drivers are?

Gave up installing windows xp because searching for the missing 6 driver is too time consuming.Already installed vista now.Running perfectly.

Agreed.I thought Vista will lag alot but turn out to be excellent.I recommend CQ users to use Vista.

Vista's program compability still isn't good as xp.I had the same problem last time with some of the engineering program(sloidworks,autocad etc).Some managed to run the programs with compability mode.

Just change the setting in advanced power setting(Vista) or power option properties (XP).

I don't think it's possible in Vista.But for me automatic lcd off after 1 minutes is already good.

Some of the forumer managed to install xp.Read all the post all find them.
By the way I suggest cloud9_lee to list all the cq notebook user and the os they use.

You can add up to 4GB of RAM.But you need 64bit OS to detect 4GB of RAM.

No problem with 3GB RAM with 32bit OS.You will get 2.75GB RAM because 256MB RAM will be used as video memory.

I think you can reduce the video memory manually at BIOS.I used to change it at other notebooks.Going to try it tomorrow.

For now I can only help you with question 3 and 4.

3)You don't have to install AMD SATA Driver.You only have to sliptream the achi driver from Raid7(something like that) folder.

4)Read here.http://www.howtogeek.com/howto/windows/resolving-setup-did-not-find-any-hard-disk-drives-during-windows-xp-installation/

Nobody have found solution for the screen brightness.You can try installing some of the vista drivers in xp but when I tried that,still left 6 unknown drivers.

Have you tried all the drivers in the 1 post?Did you tried windows vista?

Anyone here managed to install all the drivers for windows xp?

Can't you flash back to the original BIOS info?

I am guessing around RM1800.
Is your Vista Ultimate running smooth or sometimes lag?Initially I planned to install Vista Ultimate in my notebook but decided to install home premium because I thought ultimate use more resource hogging than home premium.

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For any windows vista users who are having lagging problem,you can check this site : http://www.tweakguides.com/VA_5.html

You guys can try it.Please reply here it improves vista.

Free DOS edition dosen't come with any driver.You have to download the driver by yourself.It's easy to find the driver for Vista.