If the OP (original poster) has a "new Thinkpad", as stated, and he wants to "expunge Vista", then he probably has one of the newer SATA controllers which work by default in "AHCI" mode. These controllers are NOT detected by any version of XP. They will not be detected by UBCD (Ultimate Boot CD). If you boot the manufacturers diagnostics, you may be able to wipe the drive. But you still can't install XP -- the XP install CD will NOT see the drive. There have been many comments in many threads about problems trying to install XP on newer notebooks which came from the factory with Vista.
Some have reported success by going into the CMOS setup and changing the SATA controller from "AHCI" to "IDE". If you don't have this option in your CMOS setup, you may be out of luck. A friend of mine set out down this path, and had to bring his notebook to me because he had wiped Vista, could not install XP, and had no restore disk. My advice to you is, do some serious searching online to see if it is possible to install XP and get ALL of your devices working (sound, network, wireless network, etc). Do this searching BEFORE you wipe out Vista.