HTC Desire 600 hard reset

How to reset Dual SIM Android phone
Performing a factory reset using hardware buttons
If you can’t turn HTC Desire 600 on or access settings, you can still perform a factory
reset by using the hardware buttons on HTC Desire 600.
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

Performing a factory reset from settings
1. Slide the Notifications panel open, and then tap.
2. Tap Backup & reset.
3. Tap Reset phone.
4. If you also want to delete media and other data on HTC Desire 600, select Erase all data.
5. Tap OK.
Warning! Always turn off your device before installing/replacing the battery and SIM card.