|XP doesn't natively support SATA hard drives. You need to press F6 at the beginning of the installation, then load the SATA drivers from a floppy, THEN the hard drive will be recognized.|
If you don't have a floppy drive, check the BIOS to see if you can use "IDE compatibility mode". If it's available, use it to install XP, then install the SATA drivers, then change the BIOS setting back to the way it was.
If you don't have either of the above options, you'll have to create a new XP CD that has the SATA drivers slipstreamed into it. You can use a program called nLite for that.