Downgrading Vista to XP Compaq Presario CQ40-109TU

I'm not in the same impression as you for Vista, in some points, I found VISTA has its own advantages.

Since your model was built for VISTA, some of the functions may not work i.e brightness control (Fn +F7 or F8)

However, you are not alone, many CQ40 has downgraded their notebook.

If you wish for XP drivers try the following steps.


Make your Vista Recovery cd/dvd if you haven't yet, found out here

Your model needs ICH9 sata driver to be sliptreamed in XP CD installer. If you did it right, you'll pass BSOD error.

Use Nlite to sliptream ICH9 sata driver.
A good guide to sliptream sata driver, here

Note: do NOT use sata driver from that guide, your sata driver is ICH9 given below.

ICH9 sata driver,

The driver is located in iaAHCI.inf and is called ICH9M-E/M SATA AHCI Controller, here

Nlite download, here

Some suggestions to avoid problems while installing XP:

1. Try NOT slipstream all of sata drivers, use only ICH9 --> ICH9M-E/M SATA AHCI Controller

2. Use XP-SP2, a lot more easy to use since many of XP drivers were built based on XP-SP2.

3. Burn XP installer slowly and not using the maximum speed, sometimes it create errors

4. Choose a reputable CD media, not the cheap one.

Installing Audio was the most difficult part, since BIOS incompatibility.

Please update your BIOS before installing MS-UAA, at least to F.12, here

F.24 is the latest BIOS up to this date.


Drivers for CQ40-109TU

Intel Chipset,(install and reboot before other drivers), here

Install MS-UAA before Intel graphics (include HDMI sound) and IDT sound drivers , here

Intel Graphic driver, here

IDT High-Definition Audio CODEC Driver, here

High-Definition Audio (HDA) Modem Installer and Driver, here

Broadcom Wireless, here

Realtek RTL8102E Family PCI-E Fast Ethernet NIC, here

JMB38X Card Reader Host Controller Driver, here

ENE CIR Receiver (your Vista driver), here

or if it does not work try Vista driver verified from Intel, here

ALPS Touchpad Driver, here

.Net Framework(required before HP Quick Launch Buttons), here

HP Quick Lauch Buttons, here

If you had Bluetooth, here

If you had for 7 unknown devices (buttons drivers), here

Do manual installation

Go to device manager, right click unknown device,

Choose to update driver, No to connect,

Choose install from a list or specific location, Don't search, Have disk,

Browse to the location of machine.inf.

Do it for the rest of unknown devices

Good luck

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