How to recover Microsoft Lumia 640 XL to Factory Settings and Hard reset.
- Turn off the device
- Press and hold Power key, release power key when the device vibrates
- Press and hold Volume Down key until the Exclamation (!) logo appears
- Then press sequence keys: First Press Volume Up key
- next press Volume Down key
- next press Power key
- the last press Volume Down key.
Easy hard reset from menu settings
- Select Windows Phone Settings
- select About
- select Reset your phone