It seems that a lot of people are having the same problem.
Here's a solution. In the past, when I have had this problem, I've used a wooden dowel (to avoid damaging other keys) and tapped the space bar, via the dowel, with the hammer - gently at first. Then, if that doesn't work, a little harder. If that still doesn't do the trick, much harder, then harder still. Eventually, you'll find thatthedamnedthingcracksandwon'tmoveatallandatthatpointyougooutandbuyanewlaptopwhichhasaspacebarthatactuallyworks.