2005 equinox..key won't turn and the lights don't come on?

I had been having trouble with the starter...I would turn the key and it would not budge and I would have to keep messing with it until it would finally turn on. Now the key will not turn at all no matter how long you try and the lights do not turn on and the doors will not lock. Is my battery dead?? I am a girl and I don't really know much about cars...unfortunately...My cd changer has been stuck for a while. I know there are atleast two cds in there but i just cannot figure out how to get them out. could that drain my battery??? please help. My neighbor is a mechanic but he has been too busy to ask... and I can't afford to go anywhere else right now...