In order to hard reset a Samsung A777, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Samsung A777 device will be brought back to the default configuration of a brand new device.
1. Open Menu > Settings > Left Soft key.
2. Type in the phone's password. Default password is 0000.
3. Press Left Soft key to confirm Confirm and then to select Yes. Done!