A few weeks ago I was working on my iPad and all of the sudden the screen turned pink with green lines going accross it. The iPad remains on since the sleep button continues to work. When I shut it down, the screen goes blank. I've done several hard resets (holding sleep and home buttons) and most times not even the Apple logo comes on. When it does, there is no guarantee that even the home screen comes on. Sometimes it works properly, but never for more than 10-15 mins. What can I do? Is this a hardware problem?