Hi There,
I also had same Problem and I followed below step:
1. Press power button to shut down you device
2.Press Power button+vol Up+ home key simulteneously
3.select"wipe data / factory reset" using Volume buttons to navigate and Power button to confirm.
4.Choose "Yes -- delete all user data" to confirm the whole operation.
5.After that select option "reboot system now".
6. wait for around 15 sec and there you are!! follow the steps to configure it.