If you put in a new cly. it has to be taken to the dealer to be "flashed" into the computer or the secuirity system will never let you start the car.i would start at the shift lock mechainsm as it is released only when the brake pedal is depressed.the car might still think its in gear and thus not let you take the key out try putting the key in and wiggling the gear selector at the same time.check and make sure that little button you push on the shifter to unlock it comes out all the way .sometimes they stick.if this doent work you might be looking at a lock cly. and they are not cheap,even just to have flashed its like 120$ here.Let me know if this helps good luck to you
