Judging from the photos in this [guide|25174|keyboard replacement guide], it looks like the keyboard's ribbon cable is attached to the motherboard with a [guide|25629|zero insertion force (ZIF) connector|stepid=64969].
If, when you pulled out the keyboard, the cable disconnected at the connector, you may be able to simply reinsert it following the directions in this handy guide:
* [guide|25629|Recognizing and Disconnecting Cable Connectors]
Hope this helps!