I have an iPad 3 (WiFi model only) running iOS v6.x (not sure of exact version). Anyhow, after two weeks of being not being backed up to iCloud and the iPad being left on for several days (but dark in sleep mode), when I press the power/sleep button, the screen lights up and responds with an interactive message box stating, "This iPad has not been backed up in 2 weeks. Backups happen when this iPad is plugged in, locked, and connected to Wi-Fi". Ok, I've seen this message before many times, but now when I try to answer the message box by tapping on the 'OK' button inside the box, the box will not acccept my gesture and the iPad continues to display the same box message. I've tried it multiple times. It's like the iPad is frozen in this message box. It happens both when I am plugged in to power and when I am not. Plugging in to power seems to get me back to the home screen with the message box displayed in front of it. I thought perhaps the problem would clear if I simply rebooted. I held the power/sleep button down and the box at the top of the screen stating, "Slide To Power Off' appeared. It will not let me enter a gesture to slide the arrow to the right. The box with the previous message is still displayed along with the 'Slide To Power Off' box and I still can't tap on the 'OK' button and have it recognized. In addition to the 'Slide To Power Off' and the "This iPad has not been backed up..." boxes, a 'Cancel' box is displayed at the bottom of the screen, but again. when I tap on it, my gesture is not recognized. It's like all gestures have been disabled. Since the iPad does not have a removable battery, I, of course, can't pull it and re-insert it to force a re-boot. Any ideas on how to clear this hang and/or reboot the iPad ?