Welcome to TSF!
Right click the Command Prompt icon and select "Run as Administrator"
"set devmgr_show_nonpresent_devices=1" - without the quotes
"start devmgmt.msc" without the quotes
In the box that opens, select "Show hidden devices" in the 'view' menu.
Now if you expand the section on COM ports, all the COM ports that have ever
been created will be displayed, the non present ones being in grey. You can
uninstall away anything that you don't want (right click, select uninstall).
To hide again the nonpresent devices
"set devmgr_show_nonpresent_devices=0" - without the quotes