Theres quite a lot of things that could be stopping it from working, but if its still under warentee then I'd take it back.
Things I would check
-Try a USB Keyboard and see if that works, if it does you know its the hardware/drivers and not software related
-Check out Device Manager and make sure the KB shows up and doesnt have any warnings
-Check out Keyboard under control panel and make sure its all good in there
-Last resort, start removing the retaining screws for the KB and make sure the ribbon cable is secure. If loose secure it, if secure, well I'm out of ideas!
Do any of the buttons work on the KB at all or are they all dead?