This tutorial is for Lenovo A680. I will also post the ROM for this particular device.
Hard resetting / factory resetting your phone will solve the following issues:
1. If you forgot your pattern lock
2. If you forgot your gmail account
3. If you forgot your password
4. Apps that automatically force closing
5. Stuck in Lenovo Logo (sometimes does not work if the firmware is totally damage)
NOTE: Performing hard reset will erase your data.
To hard reset:
1. Turn off your phone.
2. Press and Hold VOLUME UP + Power button. Keep pressing and holding until the phone power up, release only the power button when it power up and wait until you enter in Android Recovery Mode
3. Select wipe data / factory reset. To navigate press the VOLUME ROCKER, to confirm your selection PRESS VOLUME UP
4. Reboot your phone.
If performing hard reset did not succeed, you need to wipe the cache first in the android system recovery before performing wipe / factory reset.
I hope this tutorial helps you.. If you have any question just drop a