What XP disc are you using? Home/Pro/Media Center (retail/OEM) - with SP1 / SP2 / SP3?
If the disc is SP2 or earlier, you may need to install SATA drivers at the start of the install via F6 for SATA hard drives to be recognised.
First tell us the make & model of your laptop, & what drives does it have: floppy &/or CD/DVDrom? G