How do you get your Arduino Uno on the right COM?

Using Arduino IDE 1.x
1

When I open the IDE, it immediately says Arduino Uno on COM 1 on the bottom, but when i go to the Device Manger it says that my Arduino Uno is on COM 3 and this prevents me from communicating with my board from my computer. How do you either switch the IDE to recognize the Arduino Uno as COM 3 or how do you switch the board to be COM 1? I have Windows 7 Ultimate on my computer 32 Bit.

2

You select it in the IDE and nowhere else.

OPEN the IDE

Select TOOLS

Select PORT

And whatever you board is listed under for the COM port there is the one you need.

If the one board is listed as two different com ports you have a different issue that could be driver related.
Or related to something else you have connected that also uses com ports (usb modems etc). in which case if you can unplug that until you are running with the UNO.
Or maybe lock in one of the COM ports to a specific device. Google "windows 7 assign com port".