Hi,
Since, for your laptop you are downgrading the operating system from Vista to XP then with HP notebook.
You need to disable Native SATA support in BIOS utility and go ahead with the installation. To disable the SATA support you need to follow the below steps:
== Disable SATA native support:
1. Turn on or restart the notebook.
2. Press the F10 key when the "HP Invent / Compaq" logo appears on the screen. This will open the BIOS menu.
3. Select the "System Configuration" tab.
4. Select "Disabled" for the "SATA Native Support" item.
5. Press F10 to Save and Exit. Choose Yes for "Save configuration changes and exit now".
For more information on this visit the below link from HP.
Problems with SATA Drivers When Downgrading From Vista to XP
http://h10025.www1.hp.com/ewfrf/wc/document?docname=c01675438&cc=us&lc=en&dlc=en
if you get any problem while doing this then plz get back. Actually you need to do lot of things to downgrade from Vista to XP on HP preloaded vista operating system.
Let me know if you find any difficulties doing this..
I hope this will help you to get it work. Plz vote for me..Dreamkam