astra starting problem after ignition barrel change?

Hello
My son lost his only key to his 1998 astra 1.6 petrol. I have brought a replacement set from a breaker consisting of ignition barrel, key, chip, transponder, ecu and central locking box. I have changed the barrel and transponder so far. The car will start but cuts out after 10 - 15 seconds. The car has been left for two weeks and the bateery is dead and car frozen. Can anybody tell me if it is the immobiliser kicking in and cutting it out or would it not start at all if the transponder was not working, Thanks