If you forgot a Windows XP password, you can log on as an administrator to reset the password. Follow this:
1) Restart the computer.
2) Press CTRL+ALT+DELETE twice, then type the name of the administrator user account.
3) Type the administrator password in the password box, and then click OK.
4) Click START ->> RUN ->> Type 'control userpasswords2' ->> click OK.
5) On the Users tab, click the name of the user account that you want to reset the password for, and then click Reset Password.
6) Type a new password in the New password box, and then type the password again in the Confirm new password box, and then click OK.
7) Restart the computer, and then try to log on to Windows again.
If you forgot or lost your Windows password, you can log on as a valid administrator account to reset all users and other administrators password, without any tool. But, if you forgot your only administrator password, you can reinstall your system with Boot-CD, or reset your Windows password with a Windows Password Reset Disk if you got one, or use some Windows password recovery tool to reset the password. Windows Password Recovery Tool 3.0 is a good choice for Windows password recovery, it can easily reset Windows user and administrator password to blank without reintalling your system.