Starting problem

[celgt4]

My little son left the interior light on which, over the course of a weekend flattened the battery. I eventually had to fit a new battery but the car will not start.
It turns over on the starter and then stops. It will not turn over until the key is turned off then on again. The engine just will not catch and come to life.
Any ideas
Cheers

 

[MicKPM]

Is the red LED on solid by any chance?

 

[celgt4]

No it's not in fact it isn't on at all. The service light is though

 

[celgt4]

It was the immobiliser. It needed the key left with the ignition on. Started now!