According to the latest report in the recent wave of Windows security problems, a regular Windows 2000 CD can be used to access any Windows XP account with Administrator privileges.
The report, which originated from briansbuzz.com, states that any user with a copy of Windows 2000 can boot directly into the Recovery Console and access any of the user accounts with full access. Account passwords are effectively useless and files can be moved, deleted or copied to floppy disks and removable media.
More details can be found here.