Need help with a little problem, with my Dx when I push the lock button, or just let the screen go black, to put it in my pocket or just to simply just lay there. But after just a minute or two from when the screen turns off, its like it turns off. Except that I cant turn it back on until I take the battery out and put it back in, and then it will start back up. It does this almost every time, has anyone else had this problem? Any info on the issue would be very appreciated.