If your comm port can not talk to your Arduino, the board can still be "selected," but the comm port will not be "selected." If you see "Arduino Uno on Comm 11 [not connected]" on the bottom-right of the IDE, then the comm port does not see the Uno. If the comm port can not see the board and you try to IDE >> TOOLS >> PORT >> you will not be able to select a port. This could mean your "USB driver" is not installed on your computer.
On the "Dream" computer (and on "mine" computer) open Device Manager. Insert the Arduino USB. Wait five seconds. Inside Device Manager, open the "Ports (COM & LPT)" and you should see "USB-SERIAL....(COMx)"... if you do not, your USB driver for Arduino is not installed. My computer needed a "CH340" driver... and I see that in my Device Manager. You should see something similar on "dream" computer.