Force users to type a username and password on logon
To enable “Ctrl-Alt-Del” logon on Windows Vista Business computer, please perform the following steps:
1. Logon the system with an administrator account.
2. Type secpol.msc in the Start Search box, and press Enter.
3. In the Local Security Policy window, navigate to Local Policies \ Security Options, double-click the policy “Interactive Logon: Do not display last user name" and change the setting to Enable.
4. Type gpupdate.exe in the Start Search box to apply the policy.