Può essere che questo codice su win 7 64 bit non veda le com virtuali ?

codice:
Try
            Using searcher As New ManagementObjectSearcher("root\CIMV2", "SELECT * FROM Win32_SerialPort")

                For Each queryObj As ManagementObject In searcher.Get()
                    Console.WriteLine("DeviceID: {0}", queryObj("DeviceID"))
                    Console.WriteLine("Caption: {0}", queryObj("Caption"))
                    Console.WriteLine("Description: {0}", queryObj("Description"))
                    Console.WriteLine("-----------------------------------")
                Next
            End Using
        Catch err As ManagementException
            MessageBox.Show("An error occurred while querying for WMI data: " & err.Message)
        End Try
Grazie, Alberto