I had this problem. I read about the sticky keys problem but it didn't work.... but I did find the answer. I was told the press the spacebar down hard a couple of times... which I did... but that didn't work. Then I was told to really press down hard on it a couple of times...and that worked! So sometimes it appears that things get locked up and even though it feels like you are tapping on it. Try tapping on it a couple of times really really hard. When working properly the key should feel like it is going far. If it feels like it is going down only half way it is probably jammed up some how. Compare the key that wont work to any ones that do work. If it is only one key that is not working its probably not really a "sticky key" problem, its a physical jam up.