The easiest way to configure auto-logon in Windows XP and Windows VIsta is using the Microsoft-provided account management utilities. These work only if the kiosk is not added to an Active Directory (AD) domain. In XP, typing control userpasswords2 in the Run window brings up the required configuration attribute (See Auto Logon for Windows XP). In Vista, enter netplwiz. Figure 1 is the result in Vista. In both versions of Windows, unchecking the box indicated by the red arrow, Users must enter a user name and password to use this computer, causes Windows to prompt for a logon user name and password. These credentials are used on restart or power up to logon, eliminating the credentials prompt from the user's logon steps. Again, this only works--and the check box only appears--if the kiosk is NOT a member of an AD domain.
If you require the kiosk to have domain membership, there are two other utilities available. The first is the Sysinternals' Autologon utility, a free download from Microsoft. It provides both a GUI (See Figure 2) and a command line interface for Windows XP. Its real value is its ability to configure auto-logon even when a kiosk is attached to a domain. It bypasses the Windows utility. A different utility, also named autologon, is available for free download to allow bypassing the domain membership constraint in Vista (See Figure 3). Using these utilities is easy, but's there's a catch.
These utilities write the auto-logon credentials to either the registry or to LSASecret. In either case, they are easily retrievable by anyone with access to the kiosk. Under no circumstances should the logon account have more than the most limited network resource access. Provide additional access via application credentials, if necessary. If elevated privileges are necessary for the auto-logon account, consider using a commercial product like LogonExpert.