Open The Case Of Your Phone, Then Clean The Substances With A Thin Brush And Check If Its Now Working....
If Not, Proceed To These Steps
1.Shutdown Your Phone Let It Rest 2 Minutes.
2.Open Case
3. Remove Battery
4. Unscrew To Open The Board Processing Your Phone
5.Remove The Board
6.Reheat It With Heat Gun In 300 Degrees Celsius ( Be Careful On What You Going To Heat On Then, Kindly Revert The Steps
It Should Be Working Now.... If Not, Replacement May Be Needing
Its No Software Or Any Spy/Mal/Wares, Its Hardware
cheers, Erol
-Microsoft Community