FORGOTTEN WINDOWS PASSWORD
  Most systems have been setup from the factory without an Administrator password. This can be both a blessing, but a dangerous security risk as well. However, if you have not set the Administrator password and forget your Windows password to log onto your Windows XP system, you can use this method to clear your existing password.
NOTE: It is always best to setup a password hint when you create a password that will remind you of your password. This could help prevent from having to use this method.

1. Restart your computer is Safe Mode by restarting the system and pressing the F8 key prior to the Windows XP splash screen.
2. At the logon screen, choose "Administrator".
3. When Windows finishes loading, click "Yes" on the "Safe Mode" message.
4. Open the Control Panel (Start>Control Panel)
5. Open "User Accounts"
6. Click on your user name
7. Click on "Remove Password"
8. Close all windows and restart Windows normally.