Visual Basic.NET - Porque no puedo leer nada dentro de (HKEY_LOCAL_MACHINE) en registro de windows.

Private Sub PruebaLectura

    Dim userRoot As String = "HKEY_LOCAL_MACHINE"

    Dim subkey As String = "SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon"

    Dim keyName As String = Convert.ToString(userRoot & Convert.ToString("\")) & subkey

    Dim permission As New RegistryPermission(RegistryPermissionAccess.AllAccess, keyName)

    permission.Assert()

    ' ///////////////////////////////////////

    Dim readValue = My.Computer.Registry.GetValue(keyName, "AutoAdminLogon", Nothing)

    If My.Computer.Registry.GetValue(keyName, "AutoAdminLogon", Nothing) Is Nothing Then

        txResult.AppendText(TimeOfDay.TimeOfDay.ToString & " > " & "Value does not exist." & vbCrLf)

    Else

        txResult.AppendText(TimeOfDay.TimeOfDay.ToString & " > " & "Current value is = " & readValue.ToString & vbCrLf)

    End If

End Sub