In order to hard reset a Acer neoTouch P400, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Acer neoTouch P400 device will be brought back to the default configuration of a brand new device.
1. Hello! For starters, hold down the Power key in order to switch off the device.
2. Is it off? Then remove the battery and replace it after about 5 seconds.
3. Now press and hold the Talk + End button for a moment.
4. Keep holding those keys, and also hold down the Power button for a couple of seconds.
5. Release all keys after the phone vibrates twice.