Compaq Presario CQ40-128AU Driver for Windows XP

AMD CHIPSET
(netframework installed first)
South Bridge Driver:
Download (AMD SITE)
Download (mediafire)

AUDIO:
Install MS-UAA first:
both ms-uaa sp33867 and kb888111 are similar files.
Windows XP SP2: Download (SP33867.exe)
Download (KB888111)
Windows XP SP3: Download (KB835221)

Then restart, and install AUDIO Drivers:

IDT - High Definition Audio Codecs
SP41500 Download (ftp)
Download (mediaifre)
===========================
or try this drivers reported work in xp
(SP39671) Download (ftp)
Download (mediafire)

SP41616 Download(ftp)
Download (mediaifre)

then Install

HDMI Driver
Download
===========================
First install your audio.
Installing the Audio normally resulting in error, ignore it and proceed by manually install the drivers, read the guide here;
Manually install Audio Drivers.

If the Audio disappear after restart follow guide below:
AUDIO DISAPPAER AFTER RESTART: PART 1 

GRAPHIC:
ATI Radeon HD 3200 Graphics/Video Driver
(netframework installed first)
Download
If you have problems installing the Graphic drivers read instruction here:
Installation Guide ATI RADEON HD3200

-------------
ETHERNET:
Realtek RTL8102E/8111C Family PCI-E Gigabit Ethernet NIC Driver
Download


WIRELESS:
===========
Choose one of the wireless driver base on your specs, if you dont know, just try each driver (there are no risk and will not harm your system)
---------------------------------------------------------
Broadcom: Download

Intel: Download
(requires windows installer 3.0 installed first)

Atheros: Download (direct)
or here (atheros site)
 ==================

HP Integrated Module with Bluetooth Wireless Technology
Download

HP Wireless Assitant:
Download

CARD READER
JMB38X Card Reader Host Controller
Download

ALPS Touchpad
Download

WEBCAM
Cyberlink youcam software 2.0
Download

LIGHTSCRIBE:
Lightscribe system software
Download

Unknown devices:
Download

ENE-CIR Reciever:
Download

STILL have problems with the audio installation:
First make sure you already follow the manual guide here:
AUDIO DISAPPAER AFTER RESTART: PART 1 

then still can't figure it out? this guide may help you the audio drivers are similar:
http://getlaptopdriver.blogspot.com/2009/10/compaq-presario-cq40-416au-windows-xp.html