The membrane just got jammed funny is my guess. Take the key off. Than try to just press where the key used to be. If you need to press super hard still, it may be broken. If it is broken, there may be a slight chance to fix it, but it is mostly a mechanical feature and may be difficult to. If it works with a light press when hitting it without the key, than the key is still functional and properly putting the key back on will solve the problem. Best of luck =)