HKLM\Software\Microsoft\Windows NT\CurrentVersion\winlogon Instructions to Enable Auto Logon with Regedit Topics for Windows 7 Auto Logon Registry Hack The trick, which also its liability, is to use regedit to set a value for DefaultPassword in the registry. With Auto Logon enabled, when you restart the machine it automatically logs-on a named user. A typical scenario would be a test machine on a private network.
The idea behind the Windows 7 Auto Login is that a userName can logon at a computer without having to type their password.