Test for domain/user/password combination.

Private Sub Command1_Click()
Dim szDomain As String
Dim szUser As String
Dim szPassword As String
Dim lToken As Long
Dim lResult As Long
szDomain = Text1.Text & Chr(0)
szUser = Text2.Text & Chr(0)
szPassword = Text3.Text & Chr(0)
lToken = 0&
lResult = LogonUser(szUser, _
       szDomain, _
       szPassword, _
       ByVal LOGON32_LOGON_BATCH, _
       ByVal LOGON32_PROVIDER_DEFAULT, _
       lToken)
If lResult = 0 Then
 MsgBox "Error: " & Err.LastDllError
Else
 If lToken = 0 Then
 MsgBox "Not Valid user, password or domain"
 Else
 MsgBox "Valid User"
 End If
End If
End Sub
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