HOW TO MAKE HARD RESET FOR YOUR SAMSUNG S3 YOUR SELF STEP BY STEP :
1_Turn of the phone
2-Press and hold volum up + and HOME center button And power button.
3 -You'll see the following screen :
We'll give you several choices
_choose
WIPE DATA/FACTORY RESET
_ and choose
YES .......DELETE ALL USER DATA
and finaly after format,choose
REBOOT SYSTEME NOW