LucSkywalker:
I have installed the Arduino software to install the driver for USB/COM port.
Is there a protocol that I'm not aware of?
There is no need to install a driver for that port. It sounds like you are trying to use software serial on the hardware serial port. If so, don't.
The serial monitor can only be used on hardware serial. If you want to use a proper terminal programme on PC, same thing - hardware serial.
If you need to use an additional serial device on the Uno, that is the time to consider software serial.