ZTE Optik hard reset
Reset ZTE V55 Power Key lets you reset the tablet to default by holding the Power Key for 15 seconds.
If you hold down all three keys it will put the android guy on the screen with a ZTE in the middle of it's chest then do volume down and power and it will go to the recovery screen.
Important: Before resetting your device, back up important data to your computer using a tethered USB connection.
or1. From the Home screen, press the Menu Key and touch Settings.
2 Touch the Privacy
4 Touch Factory data reset.
5 Touch Reset tablet.
6 Touch Erase everything.
1. Touch HOME > Apps and select Settings > Privacy > Factory Data Reset. Read the Factory Data Reset information.
2. If applicable, select check marks for Erase internal storage area (media area) or Erase USB Storage.
3. Touch Reset tablet.
4. Touch Erase everything. Your device will power down and reset itself, which may take up to 10 minutes.