Microsoft has enhanced security features in XP including the the ability to create a floppy diskette to recover your password incase it is forgotten.
Click Start
Click Control Panel
Click User Accounts
Click on the account which you want to create a password disk
Click Prevent a forgotten password which starts the Forgotten Password Wizard . This is found under Related Tasks
Insert a blank, formatted disk into drive A, and click Next
Enter the password in the Current user account password box
To use the recovery disk, at the Welcome screen
Click the user name whose password is on the recovery disk
Click the question mark button
This causes the Did you forget your password message to appear.
Click use your password reset disk
This will start the Password Reset Wizard.
From this point, just follow the wizard's instructions and you will be able to set a new password.
These instructions are for Windows XP workstation standalone in a workstation. The instructions are different if the workstation is a member of a domain.