Instruction #1


1. Press and hold the Power button.



2. Choose the Power Off option, then tap OK.
3. Just wait for a couple seconds.



4. Now hold down the Power button again to turn the phone back on. 

Instruction #2


1. To begin, remove the back cover and the battery for, say, ten seconds. 
2. Afterwards, put everything back in its place.
3. Now switch the phone back on with the Power button.