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If you cannot click it down into place, chances are good it is not fixable outside of replacement - replacement shouldn't be hard if you can find the cover piece, that's the trick... finding the part.
a little bit more information would be helpful. what model system is this and is it just the strip that runs around the keyboard or is it the plastics for the actual bottom half of the system. the plastics depending on which part they are can either be a real pain to replace or as simply as snapping a new one in place.