I had trouble getting started with my RexQualis UNO. I installed the IDE, then connected the power cord to my board and then plugged my board into the USB 3.0 port on my computer.
I got a USB error. The IDE didn't recognize my board. I tried and tried to reinstall the drivers, but nothing worked.
As I was going to give up for the night, I was taking my installation apart. I first unplugged the power cord from my board. When I did this, the LEDs remained lit up. The board was getting it's power from the USB cord. So I went back in to the IDE and now my board is recognized as COM: 3.
Everything works. So if you are having this problem, try hooking your board up to your computer without plugging the power into your board. Let the USB power up your board.