I have a Karbonn titanium s99. It was working properly until last month. But suddenly all installed apps started crashing whenever I tried to open them. I cleaned some data and cache hoping it would solve the problem. But it just kept getting worse.. And last week when I switched it off and turned it on again I found that all installed apps were deleted automatically. YouTube stopped working.. Play store and dialler don't work.. I have no idea what to do.. Please help.