I have a Compaq Presario 2700 laptop - the hard drive is making clicking noises that sound like read/write head problems. I would like to replace the hard drive but have never worked on the insides of a laptop. I have done a lot of work on desktop computers - replacing all types of components and boards. What do I need to research and find out about replacing the hard drive? Are all laptop hard drives "generic"? Is this very difficult or should I be able to do this? Thanks.