Reset device in Recovery mode Nexus 7

See options for backing up and restoring your data before performing a factory data reset. To perform a factory data reset, select your device from the list below and follow the instructions. 

1. If your tablet is on, turn it off.
2. Press and hold the Volume Down button, then press and hold the Power button at the same time until the tablet turns on. You'll see the word "Start" with an arrow around it.
3. Press the Volume Down button twice to highlight "Recovery mode."
4. Press the Power button to start Recovery mode. You'll see an image of an Android robot with a red exclamation mark and the words "No command."
5. While holding down the Power button, press the Volume Up button.
6. Use the volume buttons to scroll to "wipe data/factory reset," then press the Power button to select it.
7. Scroll down to "Yes - erase all user data," then press the Power button to select it.

Note: If your tablet becomes unresponsive at any point during these steps, you can restart it by holding down thePower button for several seconds.