Keyboard Repair (Laptop)
Laptop keyboard are most commonly damaged by liquid spills (and toddlers, or both). Sometimes the damage does not appear for days or even weeks after the spill occurred. If you spill liquid on your laptop keyboard, the best thing to do is to immediately remove all power from the laptop by removing the battery and unplugging it from the mains. Then place it fully open, keyboard down, on a towel and leave it to dry for as long as necessary.
Some laptops have a 'spill proof' design. This may not, however, refer to the actual keyboard itself, but rather that liquid spilt onto the keyboard will not leak further into the laptop.
Where a single key or group of keys has been prised from the keyboard, it is sometimes possible to 'clip' the keys back into place, provided that the support mount has not been damaged in anyway. The support mounts are easily damaged because the plastics are so thin. Key faces usually have to be 'slid' onto the mount from a particular direction before being pushed down and clipped into place. You can usually ascertain which direction by study the back of the key face.
Keyboard Replacement
It is usually relatively straightforward to replace a keyboard, and usually relatively cheap. Keyboard designs vary widely between laptop models however, so the keyboard will usually need to be ordered in. Turnaround is usually 24 to 48 hours.