Hard Reset HTC Desire 510

First method:

1. In order to switch off your device press the Power key for a short while.
2. Press and hold Volume Down + Power button at the sime time for a couple of seconds.
3. When you see the three Android images, then release held keys.
4. Then press Volume Down to select option "Factory reset", and press Power button to confirm.
5. Good job! The hard reset has just been performed.

Second method:

1. If the display is off, press the Power button to turn it back on.
2. Then from Main Menu go to Settings and tap Backup & reset.
3. Afterwards choose Reset phone and select Erase all data.
4. Tap OK to confirm your choice.
5. Success!

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