Compaq Presario CQ40-502TX Windows XP Driver

First Install Netframework:
Net framework 2.0
Download

HP Quick Launch Buttons
Download

INTEL CHIPSET:
INF Update Utility - Primarily for Intel® 5, 4, 3, 900 Series Chipsets
Download (intel website)
Download(mediafire)

Intel matrix storage manager:
Download (intel site)
Download (mediafire)

GRAPHIC
if you have intel graphic:
Mobile Intel 45 Express Chipset Family Graphics Driver
Intel graphic accelerator 4500MHD
Download

If you have Nvidia graphic:
NVIDIA GeForce G 103M/ G 105M Graphics Driver (186.81 WHQL XP 32-bit)
Download

FOR NVDIA: if resulting in error use modded driver below:
Download
3-step process to install:
1. Download driver, double click and select extract,
2. Download modded INF and replace original INF in extracted folder,
3. Install and  reboot.

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AUDIO:
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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 (SP39671)
Download (ftp)
Download (mediafire)

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.

High-Definition Audio (HDA) Modem Installer and Driver
Download

WIRELESS:
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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

if error try newer version -
Broadcom BCM9431HMG
Broadcom: Download

Intel: Download
(requires windows installer 3.0 installed first)
=================

HP Integrated Module with Bluetooth Wireless Technology
Download

HP Wireless Assitant:
Download

Realtek RTL8102E Family PCI-E Fast Ethernet NIC
Download(direct) or Download

CARD READER
JMB38X Card Reader Host Controller
Download

ALPS Touchpad
Download

Synaptics Touchpad
Download
Download

WEBCAM
Cyberlink youcam software 2.0
Download

LIGHTSCRIBE:
Lightscribe system software
Download  

If you have 7 unknown device:
Unknown devices:
Download

Unzip files, open folder and right click at machine.inf, select install.