Are you running SATA controller or IDE? Check in your BIOS by tapping F-key shown on first boot-up screen. See if you can set the HDD to IDE to get XP to recognize it.
If not then we need to get the SATA drivers
in, either using XP installer prompt or slipstreaming them into the installer using Nlite.
I am a little rusty on XP installs and not at my computer to test this until Sat afternoon/eve.
Any help here?