Hello, I had purchased my S820 one year, since then it was working flawlessly till last night when somehow I lost my focus and installed Chinese theme centre of Lenovo, from where I downloaded few themes for my Lenovo S820.
After applying one of the themes and troubles started, there is an error message appeared " unfortunately, Lenovo Lock Screen has stopped" after pressing okay the message kept coming endlessly. it is not disappearing. however when I connected my phone to laptop it was detected immediately, and there are no problem in charging as well. there are two versions in this mobile one is 8 GB and another is 4 GB.