FE Keyboard Problem

I've had my FE since Feburary and it has worked flawlessly up until now. For some reason the "S" key on my keyboard barley works. If I just tap it like any other key it doesn't work and to get it to work I have to push just the top of the key really hard. It also doesn't feel right when I push it down either. So my question is do I need to re-situate my keyboard? And how do I go about doing that if so?

 

Update: I flipped my computer over to try and decide if I wanted to take it apart. When I flipped it back over the "S" was working. Upon further inspection I realized the "N" no longer worked. I took some canned air and blew under the keyboard and what appears to be a small pebble flew out. Now my keyboard is performing flawlessly once again. So if anyone else has the same problem it may not be your keyboard but something trapped under your keyboard.