Install Windows XP on Compaq Presario CQ40-324TU

Use Nlite to sliptream ICH9 sata driver.
A good guide to sliptream sata driver
here:
http://maxeasyguide.blogspot.com/2008/04/preparations-for-winxp-installation-cd.html

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

Download ICH9 sata driver,
The driver is located in iaAHCI.inf
It is called ICH9M-E/M SATA AHCI Controller
here:
http://tinyurl.com/5nbgqd

Nlite download:
http://www.nliteos.com