Hard Reset HTC First

First method:

1. Make sure, that your device is on.
2. Then access to the App list.
3. Now hit on Settings app.
4. Choose Backup & reset.
5. Select Factory data reset.
6. After that hit Reset phone.
7. Afterwards erase everything.

Second method:

1. Power off the device.
   
2. Now press and hold Volume Down + Power button.
   
3. Then you will see a screen with tree Android images appears.
   
4. Release all buttons.
5. Use Volume Down to select "FACTORY RESET", and press Power button to confirm.
6. Wait for your phone to reset itself.

WARNING !
Hard Reset will erase all of your data
All described operations you are doing at your own risk.