A youtube question Help :)?

Hi i want to make a youtube music video but i do not have a camara xD but one thing i like to do is make music videos and i was wondering out to take clips from movies like Transformers or star trek or inception and make a real awesome music video out of it but to do this i need the movie on my my cpu and i need to be able to cut uneeded seens and use the parts i want from the movie