Hard Reset/ Factory Reset Battery Charge Need 70% Up.
1. first turn off your device press power key.
2. Next Press And Hold Together Volume Up + Home + Power Button Until Show Samsung Logo View On Screen.
3.When Samsung Logo appears On Smart Phone Screen Release All Buttons.
4. This step Show Android Recovery menu on Screen Now Use Volume Down Key To Scroll and Select This Option "wipe data / factory reset" Than Press Power Key To Confirm.
5. Now Select This Option "Yes -- delete all user data" Again Press Power Key To confirm this whole process.
6. you are now last step just Scroll use Volume down key to select "reboot system now" and again press power key to done it.
Good job done it.
2nd Method
1. Now Turn On Your Device First
2. Go To Home Than Go Settings
3. After that Tap This Option Backup & Reset and then Factory data reset.
4. than Select Reset Device
5. Tap This Option Erase everything.
Wait Few Second After Finish This Process device will be auto restart.
Done.