Unplug all USB cables.

If you go into the command prompt and type:

set devmgr_show_nonpresent_devices=1

Then go into Device Manager.  Select view->Show Hidden Devices and that will show you all the ghost com ports.  Just delete them all and the com ports will all be cleaned up.

This is what I do when the com ports get screwy.

73,
Kevin
KX4KU