Help, My 2006 Citroen Berlingo 16 valve 1.6 petrol MPV wont start. No engine managment lights up on the dash. Everything looks normal. Battery turns the engine just fine but it wont take. The only thing that's changed since my last run was I transferred the key and the circuit board to a new key case. That locks and unlocks the vehicle no problem but she just won't start. I've checked for loose connections and the battery seems ok. Petrol in the tank. Help!

If you have another key, try it. Sounds like an immobiliser problem...maybe.
Does it have a fuel cut off button? Red,on L/H turret?
Is the key immobilizer key symbol flashing on the dash when you try to start it. Just a thought but did you transfer the immobilizer chip from the old case to the new case.
You haven't transferred your immobiliser chip to your new case.
Its small , black and square and sits in the corner of the case.
You can check this by holding the old key case as you would if it had a key blade still next to the hole the key goes in whilst you use your new key to start your car.