You harddrive is not found because it is a SATA harddrive and XP does not have the drivers built in for it. The only way to make this work is to:
1 - Find SATA drivers for the controller built into the notebook. (I don't think HP provides these)
2- Hit F10 when starting up to open the BIOS. Check to see if there is any place you can change the SATA operation from AHCI to ATA. (This makes the drive run in legacy mode for XP)
3- Give up, and go back to Vista. lol.
The DV2000 came with Vista on it stock. Why are you going back to XP?
Darksrb