I seem to be experiencing a rather odd problem. My Caps key will not light up when pressed, however, will type in Caps but very slowly which also slows down the computer when in Upper case. When in Lowercase all is fine. Did a restart and the problem has vanished, however, computers being what they are, it will likely pop up again. I am using a 2013 27' in iMac. Any help, tips or clues as to what I am dealing with would be very much appreciated