This is hardly a computer threatening thing but it is a little niggling. When looking through, for example, My Documents the Back button, top left on the toolbar, is no longer lit up and does not work. I've opened a folder followed by a sub folder then the subject but the button remains grey. I've no idea when this started, it was alright a week ago and I haven't done anything I'm aware of that would affect it. As I said, its just a niggling little thing, not really a problem.