Hmm... It sounds like to me that your problem is not that you cannot upload sketches. Your problem is that your PC is not recognizing your Arduboy.
You said you did not have your Arduboy on? Your Arduboy needs to be on when connected to the PC.
That should allow your PC to detect the Arduboy. A way to check if it is detected or not is to use the Windows Device Manager.
To open the Windows Device Manager program, click the Start button, find the Control Panel, click System and Security, and then, under System, click Device Manager.
When the Device Manager program opens, you can click the Ports section to see what things are connected to your PC.
There should be a Arduino Leonardo there. If there's not, let me know!