It sure sounds as though you have a very strong poltergeist working. And in answer to your last question - yes your daughter being 14 can have a lot to do with it. At that age her hormones are raging - but beyond that it is a time in which teens begin to really rebel against their parents and find out who they really are. They are caught between being dependent upon their family and wanting to be independent. So besides the hormonal shifts taking place they are also emotionally exploding inside because they aren't quite yet an adult but feel they are and can't seem to make you understand that they don't need to be hovered over like they were a child (even if their concept is incorrect). Many times poltergeist activity has nothing to do with a spirit but has to do with the teenage child only. It is difficult to say if this is what is taking place in your home. However, my suggestion to you is two-fold:

1. Each time an activity begins with the poltergeist, just firmly, without yelling, tell it to stop. Tell it that is must leave and stop disrupting your family. This may take a bit of time. And yes, if you have a family member who has crossed over and you feel they still visit you on occasion, you may ask them to help you out with this also.

2. Spend more time, if you don't have it find a way to make it, talking with your daughter. Be sure to keep those lines of communication open and let her know that you know she is going through many changes right now. Let her know that you understand the confusion she must be dealing with because she feels all grown up but is still under your control. 

I'm not saying you are too demanding on your daughter, mind you - what I am saying is, after having a son who is now 23, I know how teens get it in their heads that they know all the things in life they need to know. The best way to help them through this is to keep the lines of communication open so they can use you as a sounding board for their decisions on problems they face. But try to step back and let them decide what is best for them - guide her by making suggestions or pointing out the pros and cons to the options she has open - but don't place demands upon her as though she were five years old again - she's not - she's a young adult and wants to be treated that way. If you are already dealing with your daughter in this manner then I would say the poltergeist activity is probably not related to her but is a spirit that is probably feeding off the extra energy of your teenaged daughter. You may find you will have to get a psychic in to help you eliminate the poltergeist, if the above does not work, then I suggest you write us again and we will find a psychic in your area that can help you - we have a network of psychics across the U.S. that we can draw from.