Set the following keys in [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
"AutoAdminLogon"="1" "DefaultUserName"="myname" "DefaultPassword"="mypwd" "DefaultDomainName"="mydomain"
The domain name entry is not needed for a private LAN with workgroup.
Run the following command and uncheck the “Users must enter a user name and password to use this computer” checkbox.
control userpasswords2