In order to hard reset a Sony Ericsson W980, you should perform the following steps.

Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
Sony Ericsson W980 device will be brought back to the default configuration of a brand new device.

1. Turn on the phone.

2. Select Menu, then Settings and Backup & Reset.

3. Now select Factory Data Reset, Reset Phone, Erase Everything and Ok.

4. Your phone will now reset and restart, completing the hard reset.