How to reset pass word for window xp

A lot of times Windows XP installations do you have a password set for the administrator account. When you first boot up the machine, instead of trying your username and password, try using the username "Administrator" with a blank password. If that works you can go to the control panel and reset the password for your user account.
Otherwise you can try using the offline NT registry editor. A great video showing its use can be found here. You can also use OPHCrack found here. Both of this have a slight risk for data loss so proceed with caution if you choose to that route. If you have any further questions about the process, let me know.