That video might be able to show you how to disassemble it. It might seem a little confusing because there are no verbal instructions, but hey, it's definitely worth a shot.
well did u spill sumthing on it, well awhile ago i spilled sumthing on my GC controler and sum of the buttons sticked too but i just ran it onder sum water and let it sit for sum time and that fixed it so i dont kno or if i think u should do what i did but its really worth the try just dont keep the batterys in it ok lol!!1!! so let me kno if u tryed it adn if it work but if u dont try it im not really sure what else to do but take it sumwhere to c if sum1 has a screw driver that works!!1!!