No Comport applied when UNO plugged into computer

I am new to Arduino. Starting in Arduino Classroom with JoePardue. When I plug my new Arduino UNO board into my computer, it does not assign a comport other then com 1 which shows up in Sketch... program. In device manager it shows up as Other Device/Unknown Device with a yellow explanation point. I have tried two cables. Any ideas before I return the board?

Thanks, Terry tas.spam@gmail.com

I assume you have installed the device driver as per this page: http://arduino.cc/en/Main/ArduinoBoardUno#.UwxmSfmSx8E