Whoops, these are a difficult one to fix and once again often end in having to replace the keyboard entirely. Some very small plastic mounting arms hold the keys in place and are often broken, either that or the little clips that the mounting arms click into break. It's handy to have or get a hold of an old keyboard of the same type in order to poach the parts you need.
You may need some tweezers and a steady hand to fix these. The best thing I can suggest is to gently remove one of the other keys to see exactly how the mounting arms sit, once you have an idea of how it should look grab those tweezers and be patient, it may take some time.
We will soon have some detailed photos showing how these are assembled, until then remember to be patient and gentle.
If you seek professional advice regarding your laptop keyboard repair, the repairer will probably try to sell you a new keyboard complete with hefty labour charge to fix this for you. With the tips we have given you here, you can do your own laptop keyboard repair, fit it yourself and pocket the savings.