I was using Siri, and there was a problem connecting to the network, and at the same time an incoming call arrived. I was unable to answer the call, the screen froze with no touch capability. I was unable to get to the PW entry to unlock the phone. I tried to shut the phone down, and I was able to get the slider to power down, but unable to use the touch screen to slide the bar to power down. My phone is currently in this state and totally unusable. Can some one tell me how I can reset the device so I can get it back to functioning without having to restore the device?