You're correct in that the device manager did not see the Uno, it designated the device on com5 as unknown; if I unplug the Uno, there is no com5 displayed in the device manager.
Let me get back to you tomorrow; the computer in question is at "work". I will print out the device manager com assignments with and without the Uno plugged into the PC. I don't use clones; the Arduino Uno is a genuine part.
Obviously, I don't know much about this topic. I'll supply more information tomorrow. Thanks for staying with me on this.
John-