Sorry Big A.T can't help if it's Norton, but have you brought up task manager just before you press start to turn off computer, to see if there are any programmes still running in the background before you shut down, also you could try shut down from task manager, you'll see that above applications tab, to the right of file>options>view<windows>shutdown>help. To bring up Task manager right click on the task bar (Down at bottom of screen where programmes sit you are running, on the same part where start is, go anywhere in that area) window will come up, click on task manager > applications, if nothing is running, click on processes and see if anything can be ended there. Good Luck, let us know how you get on