We use this subroutine in the machine startup script - replace "student" with the name of your domain.
It sets the default logon domain and then hides the dropdown (it will appear if you click options or you ge the password wrong)
it also makes the default option at shutdown change to "logoff"
Code:
sub SetLogonOptions
sRegPath="HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"
o=oShell.RegWrite(sRegPath & "DefaultDomainName","STUDENT","REG_SZ")
o=oShell.RegWrite(sRegPath & "ShowLogonOptions", "0","REG_DWORD")
o=oShell.RegWrite(sRegPath & "LogoffSetting", "0","REG_DWORD")
end sub