warning : when you go for hard reset the Phone then your all user data will be deleted so keep backup before hard reset the Phone
# Turn off your phone
# Press and Hold Power button First when Phone Starting On Press Volume Down and leave Power Instantly.
# after few second a recovery menu will be appear on the screen
# now release the button
# Select “wipe data/Factory reset” by using volume key and Power key.
# Delete User data by using Power key
# after reset Reboot the Phone
Enjoy if still have a problem comment your query.