I've been using it since the beginning of January, and now suddenly, the screen won't show up. I was using it yesterday, I shut it off, and now it won't work. I've tried charging it, turning it on while it's charging, plugging it in to the computer... Nothing. I can hear that it's definitely running if I put my ear against it, but nothing shows up. The screen is just black. Has anyone else had this problem? If so, did you ever get it to work again?