I take it you dont have a spare key.
Open and dry key then fit new battery.
Push button on key, does light on key come on?
If yes, but doors wont lock/unlock you will have to re synchronise it to the car.
1. Ignition OFF, key in your hand
2. Press the central door locking button (it is either on the dash or down by the handbrake) for more than 5 seconds. Note: the door should lock then unlock.
3. When this happens, 10 seconds is allowed and the immobiliser warning light illuminates.
4. Point the key at the receiver and press the button twice, the doors should lock and unlock.
5. Check the remote control unlocks and locks the doors.
This should all be explained in your cars handbook.
laguna, September 2009