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 until the 'Power off' option appears then release.
If the device is unresponsive/frozen, press and hold the Power button (right edge) for approximately 10 seconds or until the device power cycles.