HTC Desire SV User Manual page 175

175 Other essentials
Performing a factory reset using hardware buttons
If you can't turn HTC Desire SV on or access settings, you can still perform a factory
reset by using the hardware buttons on HTC Desire SV.
1. Remove the battery, wait for a few seconds, then reinsert the battery.
2. Press and hold the VOLUME DOWN button, and then press and hold the
POWER button.
3. Wait for the screen with the three Android images to appear, and then release
the POWER and VOLUME DOWN buttons.
4. Press VOLUME DOWN to select FACTORY RESET, and then press the POWER
button.