Have you tried plugging in an external keyboard -- either via PS/2 mouse socket or via USB ? If that works, it may be worth replacing the laptop keyboard if you can find one.
Many laptops seem to approach keyboard release in one of two ways.
Either there are screws which go through the motherboard and are accessed from underneath the laptop OR the keyboard is secured by a plastic moulding (usually above the Fn keys).
You usually need a slim screwdriver to pry the keyboard out. Be very gentle, be aware that the mouse-pad and keyboard connector cables are very fragile printed circuit ribbons and the connectors on the motherboard can be easily broken too.
Try not to dislodge any keycaps on the replacment keyboard as they are tough to replace on some designs.