My 7 kept freezing and I could only get it working again by restoring it. I called Apple to get a replacement and they had me hold the down volume button and the power button to restart it and it worked. I had been holding the home button and power button to no avail. It turns out that since 7 was released the home button is no longer a real button, just a sensor so you have to use the down volume button and power button. I had no idea until now.