Yesterday my jailbroken iPhone 3G 16 gb began to shutdown to a black screen after phone calls. If I pressed the power button the slide to start screen appeared but the slide would not work. If I held the power button to the slide to turn off screen, the turn off slide would never work. In both cases the slides had the light moving across the slides but there was no response when I touched the screen. I would have to hold power & home buttons to restart the phone. After the restart/reboot it would be ok until after the next few calls then start the same problem again. It's like the touch capability is lost. Has anyone experienced/heard of this? Is my phone about to go belly up?