Don't display the last user who logged in
Windows Vista is designed so that when you press Ctrl+Alt+Delete to log in, it will display the name of the user who logged in most recently. This can be a bit of a problem if multiple users share a common PC. They may forget to check to see who was logged in previously and key in their own password in association with another user's login name. If they try this enough times, they could lock the other user out. You can get around this problem by using a simple registry tweak to tell Windows not to display the name of the user who was logged in previously:
1. Navigate through the Registry Editor to HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System.
2. Set the DontDisplayLastName key to a value of 1.