The Password Reset Disk is essentially a small file that can be used to reset your password, even if you have changed your password since creating the reset disk. This can be extremely valuable for preventing any embarrassing situations.
This is a file I keep on my tools USB stick I carry. You never know when you have someone that doesn't remember the password to log into their computer. I have had a few calls in the past asking for help.
I haven't tried it on a windows XP computer I don't think it will work, I have another tool for that.