In order to hard reset a Nokia Asha 310, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Nokia Asha 310 device will be brought back to the default configuration of a brand new device.
1. Power button turns on the phone.
2. Open Dialer and type in these buttons - 3 + *. Release them when the Nokia logo appears on screen.
3. Confirm the whole process by pressing the Call button.
4. Ta-damm! Done.