Why isn't keys on my computer working?

i have a laptop and my "a" key isnt working. obviously it seems to be working now but it goes on and off. like when i was typing the title to this question it wasnt working. anyway. this has happened a few months ago but then it started working and was fine until yesterday...yesterday it just stopped responding nd then it would come bck but then it would stop agin see its doing it now too. anyway it doesnt feel like its sticking so i dont think theres anything under the key but i herd there could be lint or hair tht could wrap round it idk if tht would mke it not respond. but i just dont wnt nything to be broken with it its my first lptop nd we cnt ffford nother one. see my key isnt working now gin. pleeese tell me wht you think it could be. im frid to tke the key off becuse i dont know it tht could brek. it do you think i will???