Alfa Romeo Repair: alfa 156 starting problem, negative battery cable, alfa 156

Question
Tried this but no luck unfortunately.
When i put the ignition on the glow light (for the diesel) goes off after a few seconds, then when i start to fire it, the starter turns (making the usual cranking noise) as if the car is about to start but the engine does not fire up. i do notice that after i wait for the glow light to go off, and the noise from the fuel pump stops, the glow light flashes repeatedly. i think the fuel is being delivered as i can hear the fuel pump. ive checked the switch under the passenger seat and that has not been triggered.
any ideas?
thanks.

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Followup To
Question -
Hi, recently bought a second hand alfa 156 2.4 JTD Wreg 2000. was playing around with the radio, lights etc and the battery went flat, so i charged it. but when i came to starting the starter would turn, but the engine would not fully start. tried changing the battery, but still the car does not start. any ideas?
thanks.
Answer -
Try this:

Disconnect the negative battery cable, wait 10 minutes and then touch the positive cable with the negative cable for 10 seconds then reattach the negative cable to the battery.

Also, explain what you mean by "not fully start".

Answer
Sorry, I missed that it is a diesel.  I am in the US and have no data on what diesel engine it is.  However, my experience with diesels is that two things tend to cause starting problems:  water in the fuel or gelling of fuel because of cold weather and valves out of adjustment.

Check the fuel filter for clues. And try bleeding the injectors by loosening the nut holding the tube to each injector.

Then mileage comes into play with condition of injectors etc.