I believe what you are referring to is the Cached Login Credentials which is part of Windows XP for computers participating as clients in a domain networking environment.http://support.microsoft.com/kb/q172931/
There are a couple of approaches to ensure that this functionality is active on the computer in question, refer to this article:http://www.secure-eserver.com/index.php?ta...ng-cached-logon
The main tools that you can use to verify if the functionality is turned on (which by default it usually is) are:
NOTE: you will need to have the permission to access the regedit and gpedit.msc tools. Refer to the article above for the settings in the registry and group policy which determine the Number of Cached logins. Once you have confirmed that the settings are set to cache the login, login to the Windows XP operating system and be authenticated by the Domain Controller. Once the user has logged in once AND the settings have been setup to Cache the logins, Windows XP will automatically remember the username and password credentials so that the user can login without having to be authenticated by the Domain Controller (i.e. logging into Windows when not physically connected to the network).