As I had to fight with WIndows XP Autologon (we have it on many computers which are used for example for CCTV), I think can write down one more quick tips how to skip Autologon feature and use different account to access computer (for example to install Windows Updates).
So, situation I was dealing with was computer with Windows XP, connected to Active Directory domain with Autologn feature enabled. After computer started I’ve seen welcome dialog and after pressed ctrl-alt-del autologn procedure kick in and login to computer with restricted account. How to skip autologon process and be able to enter different username and password?
When restricted user is logged on, press Right-Shift key and hold it pressed. Same time click Start / Logoff. When computer logs off you will get logon windows with ability to enter your username and password. In short, autologon procedure will be skipped.
If you can access computer with autologon enabled remotely using Registry Editor you can always remove certain registry keys described in article Windows Registry : Autologon in WIndows XP, then logoff and logon using desired domain or local account.