COM Port Missing from List of Available Ports When You Try to Install a New Modem

While you are using the Add Hardware Wizard to install a new modem, you may find that one of your COM ports is not in the list of available COM ports.

This behavior can occur if another program or service is holding that COM port open.

To work around this behavior, quit the program or service that is holding the COM port open, and then run the Add Hardware Wizard again.

This behavior is by design.