http://support.microsoft.com/?kbid=290260
EFS, Credentials, and Private Keys from Certificates Are Unavailable After a Password
Is Reset
Windows Home XP
1. As windows is loading up press F8 repeatedly until the Windows advanced screen
comes up.
2. Select safe mode (the version of windows you want to use click XP wait until it
loads the welcome screen.
3. Select Administrator and it will log you on as administrator without a password
(provided a password was not created in this hidden account during setup).
4. Go to Start - Control Panel - User Accounts.
5. Select your name and click change the password.
Then you should be able to change the password, shut down the computer and restart in
normal mode and use the new password you just created.
****
If you have XP Pro on your computer:-
1. At the log in screen “ ctrl-alt-delete “ twice.
2. In the User Account, type Administrator
3. Leave the password blank and press enter.
(Most likely a password wasn’t created in this hidden account during setup).
4. Go to Start - Control Panel - User Accounts.
5. Select your name and click change the password.
Then you should be able to change the password, shut down the computer and restart in
normal mode and use the new password you just created.
If you decide to set a password it is recommended that you create a Password Reset
Disk by clicking on "Prevent a Forgotten Password" link in the left pane. The Wizard
will guide you through.
http://support.microsoft.com/default.aspx?scid=kb;EN-US;321305
How to Log On to Windows XP If You Forget Your Password or Your Password Expires
http://www3.telus.net/dandemar/lostpass.htm
lists a few more options
