Hard Reset HTC One VX

First method:

1. Switch off phone by pressing Power button.
2. Press and hold Volume Down + Power button.
3. Release when u see three Android images.
4. Select option "FACTORY RESET" to browse use Volume buttons, and to choose optionPower button. 
5. After this operation phone will reboot.

Second method:

1. Go to Menu thenSettings and then to the Backup & reset.
2. Find Reset phone and select it.
3. Mark Erase all data if u want delete all media from device.
4. Press the OK.

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