First method:

1. Start by switching off your iPad by using Power button.
2. Afterwards from the Main Screen find and select Settings.
3. Select General and tap Reset.
4. After that, navigate to option "Erase All Content and Settings" and choose it.
5. Confirm the hard reset operation by tapping Erase.
6. If its necessary enter your security password .
7. After that, your device will reset.
8. Success! The hard reset has just been performed.

Second method:

1. At the beginning turn off your device.
2. Connect your iPad with your PC or laptop.
3. Then press and hold together three buttons: Home + Power for at least 5 seconds.
4. Afterwards release Power button and still hold the Home button.
5. Choose your model from the menu of iTunes.
6. Look under the Summary tab and select Restore in the iTunes.
   * Before this operation you can do back up your files.
7. Confirm option "Restore" in order to begin the hard reset operation.
8. Now iTunes should download, prepare and restore the software on your iPad.
9. Then browse to option "Set up as a new iPad".
10. Afterwards you can enter a name for your device.