14" ibook Dual USB no longer running from the battery

I got my ibook 800mhz dual USB 14" out a few days ago but it wouldn't start from the battery so I turned it over to check the power with the LED's and they all lit up. Plugged it into the mains with the mains adapter and it started fine. But as soon as I pull the plug out it goes dead. As I've had the ibook for a few years now and have used it a lot, my first reaction was that the battery was dead. Just to be sure I tried a few things out. Reset the PRAM and the power management system but no joy, so I ordered a new battery thinking that this would solve the problem but it hasn't. The machine still goes dead. I've taken the back cover off and had a look for loose wires but it all looked fine. Other things I've noticed:

1. With the second battery the machine will start up but will die just before getting to the login screen.

2. The original battery will not even start but the Num lock LED works and the screen will flicker slightly.

Has anyone got any suggestions ? Thanks in advance for your help.

Anyone ?

Are you sure your not suffering from the Logic Board problem???? It may just be freezing when you start it up..

So it works when you have the power adapter plugged in, correct? It will not work when ANY battery is in as the main source?

If thats the case, there is probally something wrong with the battery connectoer to the logic board. You may want to check the apple site to see if this is a common issue with your model iBook. That would be the first thing that I would do.