same happened with me after two year use of nokia lumia 925 i bought in dec-2013, one kids playing subway surfer and mobile got heat after one hour i use fb than mobile hanged i restart mobile by using volume and lock key button but than only nokia symbol pop-up and than dead... nokia care said that they will send mobile at banglore for reparing and service charge will be cost about Rs.9000/- so denied and got back and given at pvt repair shop but they couldn't repair it.