Spills cause all kinds of damage.  You may have to replace the keyboard.  Click here to buy one or try Dell Spare Parts.  I take it you have an Inspiron 5000

Or you could use an external KB.

Pull out the keyboard and wash that part of it thoroughly with water. If it's been a while and the root beer is dried, it may take longer. Work the keys and make sure they feel clean and normal Then immediately spray or rinse it thoroughly with Freon TF electronics cleaner. This is available in spray and bottled forms at any electronics store, maybe even Radio Shack (though likely at four times the price). You want to remove all traces of water with this. Allow to dry, then reinstall.

When I have keys that don't work I pry up the edges and run a dull kitchen knife knife around to clear away the 'dried' syrup in your root beer or my Pepsi that dryed on the underside of the key on the keyboard.If you have keys that are still working it is not electrial short, it's dried soda pop that's preventing proper contact in the electrical circuit. Next time spill the soda on your self not on the keyboard or have a kitchen knife ready the next clean up. :-)