Windows XP Automatic Logon
Why it's so hidden is a (yet another) Microsoft mystery. But here is how to make your Windows XP startup automatically go straight to the desktop without prompting to log in.
Boot your Windows XP to your desktop
Click the Start menu and choose Run…
In the run window, type control userpasswords2 and press enter
A window like this will appear:
Uncheck the Users must enter….. checkbox.
When you click OK, Windows XP will prompt you for a default username and password.
Now, set the User name and both password fields to match what you had been using to log onto your computer.
Click OK and you'll be returned to your desktop. Reboot your PC to test/verify the change worked.