My sister gave me her old macbook when she got a new one. I had an identical one that wasnt working right so i got rid of it and was excited to get a new working computer. Well it didnt quite work. the power cord was dead and after playing around with it i found it to be unfixable, so replaced the power cord. Once that was out of the way i found the battery was dead and wouldnt charge, just like my old mac book, and my old ibook, and my ipod, and like is starting to happen to my iphone. So i replaced the battery, it didnt work at first but i found that the problem was the battery wasnt sitting in the case correctly because the case is cracked in multiple places, just like happened with my last macbook. Notice a trend? well now apple products make great gifts, however i certainly would not advocate giving them half a penny of my own money for their garbage gear. the only reason anyone would have any reason to purchase one aside from being trendy is the reliability and stability of OSX, which aside from their poorly made hardware i must give credit where credit is due. ok now that my rant is over, ill return to my tale of fixing the macbook, which worked perfect for about two days after the new battery and then i found myself unable to type or use the mouse. Frustrated i set it aside for a couple weeks. One weekend i found myself unusually motivated and decided to crack it open and see if i could remedy the problem. I would suggest you visit http://www.ifixit.com/Device/Mac (great resource) and walk yourself through the steps before attempting to crack it open.
i watched a youtube video on the proper way to open it up but found that the steps they took to open the laptop didnt work out so well when i tried to follow them. so i would suggest to start by removing the screws inside the battery space and work your way around. Youll need just a regular small phillips head screwdriver but you also may need a torx set depending on the model mac you own. I would say that if you dont have a set you should pick one up along with a tri-wing screwdriver. I found my set at Frys.com They dont cost much and if you plan on doing any future electronic repairs they are a gift from the tech gods to have laying around. ::IMPORTANT:: you MUST keep track of the order you removed the screws and seperate them from each other. I kept a notepad and just wrote down where i removed the screws from and folded them into the bottom of the paper. Trust me i got a few mixed up and it was a nightmare to get them back in the right spots. inside the battery case remove the screws from the side facing the screen. remove the bezel and any remaining screws.
next remove the screws from where the battery connects. Do not remove the two screws directly next to the battery terminal connection.
on the outside wall of the battery case remove screws 2, 4, 5, and 7 ONLY.
then remove the screws from the back of the laptop
remove the screws from the back and outside edge
now carefully remove the top part of the case that the keyboard and trackpad are built into. i think this may be different if you have the unibody mac or macpro so be sure to reference youtube or google before trying to pry the top off of you laptop. it wont come easy. just be very patient and careful as possible and work your way around the case. if its not snapping open make sure you didnt miss a screw. when you do get around the entire edge gently life up on the top and use a screwdriver to detach the ribbon cable from the keyboard/trackpad from the motherboard. dont rip it. if ya do youll end up spending 100+ bucks on replacing it. when you get it off, take time to clean up the guts with a can of compressed air and some qtips and first aid rubbing solvent. Dont soak the board or any of the components thought. mine was filthy. so after cleaning and poking around i found that there are 3 momentary pushbutton contacts sealed beneath a piece of metal where the trackpad is. something was bent or deformed and was pressing on the button. i used some fabric and cleaner from an eyeglass cleaning kit and a really thin ruler to get the cloth underneath the metal sheet to clean around the pads.
so i tried cleaning but that didnt help the mouse click much. i was kinda stumped. as a last resort before ordering a new one i took a tiny piece of foam from the eyeglass cleaning kit and gently nudged it underneath the side that was making the button stick. well then i retraced my steps and put it all back together. closed it up and popped the battery back in. started it up and......NOTHING! !@#$%^&*( is what came out of my mouth. after steaming for a few i opened it back up and put in the old ram chips that i had replaced for two larger ones that i had laying around. well it said they would work but with the old ram it it started back up just fine! relieved i opened up safari and typed in some random stuff into search. keyboard works. clicked and double clicked. opened a few things. trackpad worked. wow looks like i fixed it. i cannot gaurantee that if you have the same problem the resolution will be as easy or free for that matter, if the damage or defect is great enough and your sufficiently attached to your idevice it would perhaps be in your best interest to purchase a new one, but if you wanna save yourself the 100+ dollars, try this first. I would like to reiterate that you should seperate the screws and take notes. and do a google search or youtube and watch someone else do it first with your specific model before attempting any repairs. other than that, best of luck!