Without a sample or description of the settings being used, its hard to diagnose. My suggestion would be to set the mode to AUTO, take a few pictures, and check results. This pretty much overrides any erroneous settings you may have inadevertantly made in the other modes. If these AUTO pictures are correctly exposed, you probably have a setting (like exposure compensation, auto braketing, ND filter, etc) set incorrectly for the other modes. If the AUTO pictures are incorrectly exposed as well, you may have a problem with the camera.