I have a two year old Dell Inspiron fifteen forty five laptop. The number keys work only sporadically. If I keep tapping on one it will eventually start working most of the time, and then others will start working sporadically also. No other keys have a problem. Then after being shut down for a while the problem gets worse again. I dont even know if this is hardware or software, although the fact that it gets better after attempting to type numbers for a while leads me to think it isnt hardare. Any solutions?