make sure the Arduino is plugged in (and the green light is lit). Go to the Device Manager (From the Start Menu, select Settings->Control Panel. Double click on System and select the Hardware tab. Then click on the Device Manager button)
Look for an entry under Ports (COM & LPT) that says USB Serial Port (COM) the COM number may vary but it should be something like COM3 or COM4. The COM stands for "communication", and each one has a unique number, known as the COM Port number. In this case the COM Port number is COM3.
If you don't see the COM port verify the Arduino is plugged in
should i click on "update driver"?