Hard Reset HTC Desire SV

First method:

1. Start at Home screen, tap Menu button , and then go to Settings.
2. Tap SD & phone storage option then Factory data reset.
3. Tap Reset phone, and then mark Erase everything.

Second method:

1. Remove the battery from HTC device.
2. Replace batter after couple of seconds.
3. Press and hold the Volume down button, and then briefly press the Power button.
4. Wait for the screen with the three Android images to appear.
5. Then release the Volume down button.
6. Press Volume down to find Factory reset option, and then press the Power button.

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