how to reinstall system in samsung galaxy grand duos

Solution
Press and hold volume up button,home button and power button simultaneously until Samsung logo appears.Wait until recovery menu appears, then navigate to "wipe data/Factory Reset" using the volume keys, then press power button to confirm.
Press and hold volume up button,home button and power button simultaneously until Samsung logo appears.Wait until recovery menu appears, then navigate to "wipe data/Factory Reset" using the volume keys, then press power button to confirm.
 
Solution