Type *#0*# and check whether it is working or not if nothing is heppen just off your phone and on again.. if nothing is heppen go to nearby services center if your phone in under warranty..
settings>advance feature>palm to captureif its not available installs good lock and open good lock in good lock screen click on one handed+ application and install it also. after that open one handed+ and you'll see screen capture option tremendously
if you cant find in setting>sound>ringtone option then install ringtone cutter from play store choose your favourite songs cut it app will ask you to set for default ringtone then hit ok that's it done
