[2005] Accessing Device On USB Port?

I have been doing some research into accessing devices on a USB port and it's kind of helped, but not really. From what I understand, I can use the IO.Port namespace to access a device on a USB port (usually). Let me know if this is incorrect.

First, I made a simple program that looped through the ports available. I get COM1 and COM3, but I have 4 USB ports. Where are the others?

My
Dim comm As New List(Of IO.Ports.SerialPort) 'list of comm ports
For Each PNstr As String In IO.Ports.SerialPort.GetPortNames() 'get a list of Com Port Names

[Code].....