How to Install Windows XP on Compaq Presario CQ20-125Tu

The XP Driver You can get it here

HP/Compaq do NOT support XP for this model.
They only support XP for their Business HP/Compaq models.

Use XP SP2 only, most of XP drivers were built based on XP-SP2.

If you don't have XP with SP 2,Download here: 
Download

or follow this url: (http://www.microsoft.com/downloads/details.aspx?FamilyID=049C9DBE-3B8E-4F30-8245-9E368D3CDB5A&displaylang=en)

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

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

ICH9 sata driver, the driver is located in iaAHCI.inf and is called ICH9M-E/M SATA AHCI Controller
here:
Download