If it doesn't look broke, chances are it isn't. My right-shift key came off a while back, and it took some time, but I did get it back on. Really take a look at how it goes on, and you'll probably be able to figure it out. My problem was that I was use to putting on PC keys, and figured I could just push the key back on. It isn't like that. I ended up bending a small metal hook that made the whole process much more difficult. When I finally got out a little flashlight and really took a look at how it worked, I was able to bend the small hook (on the laptop itself, not the key) back to where it should be, set the key in place, and give it a little twist. Honestly took about 30 minutes or so. I remeber I used a bent paperclip to help guide the key into place. Anyways, I don't know if this helps or not. At least, if it doesn't look broke, I'd guess that you could still get it on without taking it in.
maikutis