Over time, it is not abnormal for keys to fall off a laptop keyboard with normal use. If your spacebar key fell off your Sony Vaio laptop keyboard, you can replace it by reconnecting the inner parts of the keyboard key. Unlike the other keys on your keyboard, the spacebar has a metal bar that acts as a spring mechanism making replacing the spacebar key is slightly different than other keys. Replacing the spacebar key does not require any special parts unless the key is broken or you lost the original parts when the key fell off.
Turn the spacebar key over, and locate the metal bar that runs across the key. The metal bar is in a wide U-shape. Make a note of how the metal bar attaches to the key.
Insert the tip of a flathead screwdriver beneath the metal bar. Pry it away from the plastic tabs on the back of the spacebar.
Place the metal bar on the empty spacebar key slot so that the bottom of the U-shape fits into the tabs along the bottom of the empty spacebar key slot.
Place the spacebar key over the empty key slot, lining up the tabs along the bottom back side of the spacebar with the metal bar in the key slot.
Press down firmly and evenly with all four fingers of one hand to reattach the spacebar. You will hear it audibly click back in place.
If any of the tabs are broken on the spacebar key, you must replace the key itself.