Hi there
Your XP CD probably doesn't have the SATA drivers installed.
To re-install Windows XP in this case you have 2 choices
1) Slipstream the SATA drivers and create a new Windows XP disk -- just google SLIPSTREAM WINDOWS XP there's loads of references.
2) You *might* in the BIOS have an option for running SATA drives as legacy IDE drives -- turning this option on should allow you to install your Windows XP cd --then you can add the SATA drivers after install.
Cheers
jimbo