Nexus 7: restore to factory default

Even if I never "hacked" my Nexus device after some month (I suppose due to application installation), my device crashes and, after reboot, i was stuck on Google boot image.
I try to leave it an hour booting with no success. So... factory reset.
Yes, but... how I can run a factory reset for a crashed device? Reading online there are some forum posts with combination that I honestly didn't understand.

Here the combination I tested many time to wipe your device:

  1. Reboot your device pressing Power Button + Sound Down Button, at the same time until you can see the fast boot menu
  2. Using volume buttons move to Recovery Mode menu and then start it using the power button
  3. Your Nexus 7 will reboot and, after a while, you should see the android robot with a red exclamation mark and the information no data on the screen.
  4. Here press Power Button +  Sound Up Button at the same time for about 2 seconds and then release the two buttons at the same time. Recovery menu should appear
  5. Here you can choose, moving into menu with the sound buttons, the Wipe Data menu (and if you want Wipe Cache)
  6. At the end you have a Reboot entry into menu to restart your device.

Hope this help