Volvo S40. Replace battery. Won't crank or start ????
 

I have replaced my old battery with a new one. I wanted to start the car but no crank no start. Shows a immobiliser message. I have tried everything but my car won't start. It was fine before changing the battery. Volvo S40. 2.0 litre diesel. 2006 model.
Any suggestions ? Thanks

I have read several times to lock/unlock the doors 5 times to reset the immobilizer. Just passing on what I've read, never actually had to use it.