My backspace key is cranky. Used to be, I could press it and hold it down, and it would zip backwards through my text and delete stuff. Now, when I hold the key down it Wipes. One. Character. At. A. Time. I can press it as fast as I want, and it'll backup/wipe out one character/space with each stroke, but it won't take off and roar anymore. What have I done to my keyboard, and how can I fix it?