I have had a pocket PC for the last 2 years or so. And suddenly the screen just turned black. It works when I have the power cable connected. But not if I just want to use it on the battery. Do I have to change it. I didn't know I had to do that (dumb me). Or can it be something else. Is it worth a shot? Is it hard to do? Or is it totaly safe to upen it up. Like a cell phone?