Oh crap! That's not one I can answer if the whole scene is one object now, does it have a + next to it (ie:it's all grouped into one) if that's no help I'm afraid I'll have to hope that someone else can help you out then, it's a bit beyond my knowledge. It may help if you post a couple of screen shots for people to look at, maybe one of the scene and one with the outliner in it so people can get an idea of what you are dealing with. Sorry i can't be of any better help, good luck anyway!