I repair laptops for a living..
It's just best to get the keyboard and replace it. The keyboards are cheap and readily available on ebay or amazon. Maybe 13-15 dollars..
Fixing the key can be a son of a gun, especially if the little plastic pieces that hold the missing key is missing.. Replacing the keyboard is easy, pry off the on button/light assembly above the keyboard.. use a small flathead screwdriver to pry from the right side.. there is an indentation for you to use..
once this part is off, there are either 2 or 3 screws at the top *they are black* that are holding keyboard in place.. lift keyboard back from the top. And, there is the ribbon cable that goes to the mb.. even has a little 'handle' to remove it..
I can change the keyboard in less than 5 mins... its that easy