Visual Basic - Validar usuario y contraseña contra Server NT

Saludos...

Cómo puedo desde una pantalla de captura en VB6, validar contra un servidor NT4, el usuario y contraseña capturado.
Devolverme por lo menos si existe o no con esa contraseña...

Gracias

Fijate con esto:

Private Declare Function LogonUser Lib "Advapi32" Alias "LogonUserA" (ByVal lpszUserName As String, ByVal lpszDomain As String, ByVal lpszPassword As String, ByVal dwLogonType As Long, ByVal dwLogonProvider As Long, phToken As Long) As Long

Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long

Private Const LOGON32_PROVIDER_DEFAULT = 0&
Private Const LOGON32_LOGON_NETWORK = 3&

Private Function CheckWindowsUser(ByVal UserName As String, ByVal Password As String, Optional ByVal Domain As String) As Boolean
Dim hToken As Long, ret As Long
If Len(Domain) = 0 Then Domain = vbNullString
ret = LogonUser(UserName, Domain, Password, LOGON32_LOGON_NETWORK, LOGON32_PROVIDER_DEFAULT, hToken)
If ret Then
CheckWindowsUser = True
CloseHandle hToken
End If
End Function