my dell latitude d600 won't turn on,even if I plug the charger in?

I have a Dell Latitude D600, one evening last week I turned it off & went to bed. When I tried to use it the day after I couldn't turn it on. So I plugged the charger in & after a while I tried again, this time the orange low battery light flashed at me & it wouldn't come on. I then noticed that the light on the charger wasn't on. I unplugged it & then plugged it back in & the charger light came on, however when I plugged it into my laptop the light went off. I have tried 3 different chargers & the same happens each time. My laptop remains off. Pushing the on button produces a faint red flicker on the system battery indicator. When I check the batterys LED all 5 of the green LEDs are lit up. Any ideas of what to do?