The pictures used to be shap. no alle the pictures are not sharp. What can be wrong?

There may be a fault requiring service (probably not economically viable if they won't do it under warranty), but before you go there, does this camera have a "Macro" feature? This is usually represented by an icon that looks like a flower. If you have set that on, the camera goes into an extreme close-up mode and won't focus on items at normal distances.