Restore system to factory default. Use one of the following methods to restore the system to the factory default: 1. Obtain recovery media on DVD or USB from Lenovo's download site or the support center. Use the instructions in this link: How can I create Recovery Media (DVD or USB), or order Recovery Media (DVD or USB) from Lenovo.
Turn the phone off. Press and hold the following keys (on the back of the phone) at the same time: Volume Down Key + Power/Lock Key for approximately 10 seconds. Release both of the keys when the System recovery screen is displayed. The following options are displayed: Continue Power up, Safe mode, Factory data reset, Wipe cache, and Power …