Hard Reset HTC One V

First method:

1. Switch off device by holding Power button.
2. Push and hold Volume Down + Power button until you see three Android images.
3. Browse by Volume buttons, and to choose option use Power button.
4. Now find "FACTORY RESET" and select it. 
5. Phone will reboot.

Second method:

1. Start from Menu -> Settings -> Backup & reset.
2. Then tap Reset phone.
3. If u want delete all data (all the media) select Erase all data.
4. Tap OK.

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