I put the Ardunino Uno driver into Com 3? Would this be a mistake?
Did you get this sorted out? Com 3 is quite possibly correct (my Uno shows up on Com 3 with the USB port I am using).
Go to Device Manager and expand the section Ports (COM & LPT).
If you view the properties of the com port there the details should identify the Arduino on that port - if it is plugged in at the time. On mine the manufacturer shows: http://www.arduino.cc
If it says something else, check the other com ports.