Resetting the HTC Hero
It seems the ‘Factory Reset’ option in the ‘Security’ setting of the HTC Hero has been removed. Here’s a way of doing a hard reset that actually works.
Switch off the phone
With the phone switched off, hold down the “home” (house) and “back” (the arrow in the lower right corner) buttons
Hit briefly the “end call” button while still holding the “home” and “back” buttons.
Release the “home” and “back” button, a white screen containing technical information should appear, with a red message asking for hitting the “menu” button.
Hit the “menu button”, the Hero will now boot with factory settings.
(originally posted by Oskyldig on a Google forum)