you could be unlucky with a keybaord deect of a loose ribbon cable but its much more likley a lock or shifit key has been activated, is there an option to renter the bios and set to defaults, can you start in any safe modes and get the keyboeard to work.
Reseating a loose cable can range from reaaly easy to a pain depending on how easy its is to open up the case, thugh your warranties still in palce and you should be getting tech support!