Laptop keyboards are the bane of most IT pro’s existence. Most shops you take it to will advise you to replace the entire keyboard. It’ll be a $100 or less fix.
What happened? Spilling caustic liquid is the most common problem. Coke and keyboards are a bad combination. Any citrus juice as well. Cat pee is also a common cause, but even water can do it.
Barring replacement of the keyboard by an authorized service provider, pick up a USB keyboard at Wal-Mart and use it instead.