If you forget your lock sequence and backup PIN, you’ll have to perform a hard reset to gain access to your phone.
Performing a hard reset deletes all of your user data, which includes pictures, videos, and music saved to your internal memory. Please make sure to back up your information prior to performing a hard reset.
Turn the phone off.
Press and hold the following keys at the same time: Volume Down Key + Power/Lock Key .
Release both of the keys when the System recovery screen is displayed.
Press either of the Volume Keys to highlight Factory data reset, then press the Power/Lock Key .
Highlight Continue reboot to simply restart your phone without performing a hard reset.
The Factory data reset screen is displayed. Press either of the Volume Keys to highlight Yes (or No to exit), then press the Power/Lock Key to continue.
Your phone will perform a hard reset.