the keys can be removed and replaced if necessary. You can find new ones on Ebay for 2-3 USD.
I have removed and installed sticking keys on my Latitude D600 at least 10 times and all original keys are still working. Poor keyboard for a top-of-the-line business laptop.
Since the keys are attached differently for lots of models, you will have to see how yours are attached. Usually if you pry the spacebar up using a screwdriver, starting left or right of the spacebar, it will come off nicely. Be careful - this stuff is fragile !
Usually the metal bar or a plastic hinge has come loose and can be re-installed without problem.