Cannot get rid of graining and white out

Hi,
I have received a response to my prtoblems of severe graining on indoor shots, and white out to outside shots on my Fuji E550. The suggestion was the ISO setting.
I have now been through the whole user manual checking all settings and generally resetting to auto in all cases which is ahere I would have expected it to be. the camera is almost universally used in Auto and nothing more special.
The problem is still there and is the same as has been reported by others. This change happened suddenly and without any change having been made to the camera?
Any other suggestions please?