I replaced a modem on our fax computer. The modem I took out was on com port 3. The com port in the device manageer is com1I uninstaled the modem before removing the old modem, replaced with a new modem and added driver.when I try to run a diagnostic I get error "port already open". When I removed the new modem and put the old one back I did not get that error message. How can I close the port on Com3 so the new modem can use it?