Numero de Serie HD no me sale

Hola!

Estoy intentando sacar el número de serie del discoduro, el que te da el fabricante, pero me sale siempre en blanco...

He visto varios post pero a mi no me funciona.

        Dim disco As New System.Management.ManagementObject("Win32_PhysicalMedia='\\.\PHYSICALDRIVE0'")

        Try
            MessageBox.Show(disco.Properties("SerialNumber").Value.ToString, "Número de Serie", MessageBoxButtons.OK, MessageBoxIcon.Information)

        Catch ex As Exception
            MessageBox.Show(ex.Message)

        End Try

 Dim mc As New ManagementClass("Win32_BIOS")

        Dim moc As ManagementObjectCollection = mc.GetInstances()

        For Each mo As ManagementObject In moc

            MsgBox(mo("SerialNumber").ToString())

        Next

    ' HD físico.
        Dim mos1 As New ManagementObjectSearcher("SELECT * FROM Win32_PhysicalMedia")

        For Each mo As ManagementObject In mos1.Get()

            MsgBox(mo("SerialNumber").ToString())

        Next