How to Enable Classic Logon in Windows Vista
The Welcome screen in Windows Vista, just like the one in Windows XP, displays the user accounts for easy logon. This is certainly convenient, and most users likely prefer this method of logging on, but since I am security conscious and somewhat paranoid I prefer to have Windows set up to use classic logon (e.g., all user accounts are hidden from the Welcome screen and both a username and a password are required to log on). The reason for this is that displaying the user accounts on the Welcome screen makes it a bit easier for a potential hacker. (Before you ask why anyone would want to hack into my personal computer—did I mention I am security conscious and somewhat paranoid?) Besides, I think it looks cool to only have the username and password fields on the Welcome screen.
The classic logon prompt from Windows XP is not available in Windows Vista, but that doesn't mean it is no longer possible to require that both a username and a password be entered at logon on a stand-alone computer. To accomplish this, run "secpol.msc" as administrator, navigate to , double-click on the policy "Interactive logon: Do not display last user name," and enable it. That's it! The Welcome screen will now require both a username and a password, and no user accounts will be displayed on it. You may also want to disable the policy "Interactive logon: Do not require CTRL+ALT+DEL" while you're at it.

Enable the policy "Interactive logon: Do not display last user name" to get classic logon in Windows Vista.
If you use Fast User Switching, you will be pleased to know that the feature still works: just click on "Switch User" on the Start menu, then type the username and password of the other account you want to log on with. Fast User Switching does not work with the classic logon prompt in Windows XP, so this is a welcome improvement for people like me who use that feature.