1999 Isuzu Rodeo Question Turns over but wont fire

Engine Mechanical problem
1999 Isuzu Rodeo Question 4 cyl Four Wheel Drive Manual 18000k miles

Hi,
It's a 2.8lt Turbo diesel fitted with an immobilizer which seems to be fuctioning properly. Plenty of fuel, but feels like no fuel is getting through or something? There's just no sign of actually firing, won't roll or jump start either. First time this has happened. The radio was left on for a couple of hrs before it wouldn't start, but had started about an hr before that. I also noticed the glow plug light on dash was going off very quickly today after not being started since yesterday. It's usually stays on for about 15 secs, quite a long time the first start, then any future starts in same day only a coulpe of seconds. I've included as much info as possible, hope you can help. Cheers Susie