Resetting the HTC Endeavor hard reset
Turn off your HTC Endeavor. Press both Volume keys ( or only volume down) and POWER on the phone. When a warning message is appear press Volume down to restore manufacturer default. Press Vol down to reboot.
orPerforming a factory reset via settings
The most convenient way to do a factory reset is via the settings.
1. From the Home screen, press MENU, and then tap Settings.
2. Tap SD & phone storage > Factory data reset.
3. Tap Reset phone, and then tap Erase everything.