Hard Reset NOA N7

First method:

Hold down the Power button for a short while to switch off NOA N7.
After that press and push Volume Up + Power button for a few moments.
Let go of all buttons when you see Recovery Mode on the screen.
Now select "wipe data/factory reset". Use Volume buttons to navigate and the Power key to accept it.
In this menu choose "yes" and press the Power button once.
At first select "reboot system now" by using the Power key.
Well done!