Important Make sure to back up important data you have on the device before you perform a factory data reset."
HTC Hero Hard Reset Procedures
1. With the phone turned off, press and hold the HOME and BACKand then briefly press the END CALL/POWER button. The reset process will start after a few seconds.
2. Wait for the phone to finish the reset process and then press MENU.
Tip : If your phone hangs or freezes, remove the battery then wait for a few seconds, and then re-install it. After re-installing the battery, turn on the phone.