hmm the mother boards have a slot or socket in them to attach the processor. there is no soldering needed. the magnetic field from the soldering gun could fry the board on contact. the motherbaord is attached to the case with some pole screws. and the case matters, just not for looks but the way it is designed to flow. my old compaq computer
came with it's proprietary case and the fans would work 24 hrs a day. i changed the case because i needed to use more drives in it and the fans only come on ocassionally.