In order to hard reset a HTC Pure, you should perform the following steps.
Remember! Hard reset will delete all the data on your device; pictures, contacts, messages, apps and more.
HTC Pure device will be brought back to the default configuration of a brand new device.
1. Power up the phone with Power button.
2. Now press'n'hold both Volume Buttons and Power button for two seconds.
3. Start the Factory Reset process.
4. Wait for your phone to reset and restart.