nissan wont start

my 54 plate diesel kubistar van has been parked up since feb this year due to me gettin co. van, occasionally id fire it up but battery needed charging last time so done that, wont start, towed it, wont start, fuel up to injectors battery well healthy just wont start, the git i have however noticed the engine immobiliser light stays on when ignition on read the book and here i think is the prob. the key is well manky does this mean ive gotta shell out for new key and then possibly still have van that dont go does anyone know that a combination of a totally flat battery and dodgy key cause the immobiliser to kick in

often u find when a vehicle stands for a prolonged period and having its battery die youll find that the alarm system would need to be reprogrammed.

ive got a nissan skyline 2.8 gtx .im having problems getting injector pulse.ive started it by adding direct power to injectors