Press and hold the Power button for 10–20 seconds
Press and hold the Power button and Volume Down button together for 10–20 seconds
Press and hold the Power button and Volume Up button together for 10–20 seconds
Press and hold the Power button and Home button together for 10–20 seconds
Let the battery drain completely
Remove the battery if the phone has a removable battery
Use a hardware reset or force-off method specific to your phone model