A soft reset can resolve issues like continuous resetting/rebooting, device crashing, freezing, won't ring or vibrate, can't make or receive calls, device locks up, and keypad doesn't respond.
A soft reset (turning the device off then back on) is similar to restarting a desktop computer and is one of the first steps in troubleshooting a device.
In most cases, a soft reset won't affect data on the device, unless the battery is very low.
Press and hold the Power button (on the right edge; below the volume buttons) until the Power off prompt appears then release.
If the device is unresponsive/frozen, press and hold the Power+Volume Down buttons for approximately 12 seconds or until the device power cycles.
Allow up to 60 seconds for the reset to complete.