It will remove all the data ,contacts and apps that you installed
1. With the phone turned off, press and hold the HOME and BACKand then briefly press the END CALL/POWER button.
2. Press the ENTER button to begin the reset process.
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.
HTC Tattoo Restore Factory Hard Reset Format Phone.So lets start the HTC Tattoo Restore Factory, HTC Tattoo Hard Reset.Turn Off the mobile phone for few mints.HTC Tattoo Remove Pattern Lock.
Restore Hard reset will set your phone in origional factorry settings. It will remove all the data and apps that you installed. Your contacts will be removed and you have to add them again.