The only other thing I might suggest is that you go through the camera menu to make sure that the shutter button is also set to focus - it's possible that focus was inadvertently set to back button. Not likely but you never know. Good luck!!
AS we all know, a good camera does not a good photographer make. A bit of skill is involved and some luck never hurts either, along with the right settings for the equipment in use at the time! No hurts no rudeness, no worries. Keep shooting!