You're on a Mac, right? What version of OS X? What board?
Did you try a different USB cable? And try connecting the board straight to the computer without going through a hub or keyboard, etc.
What were you doing before it stopped working?
You're on a Mac, right? What version of OS X? What board?
Did you try a different USB cable? And try connecting the board straight to the computer without going through a hub or keyboard, etc.
What were you doing before it stopped working?