iBook G4 won't turn on

Hello all,
Forgive me if this has been covered. I searched a bit, and nothing seemed to match my problem.

2004 G4 iBook, I've replaced the hard drive, RAM, and updated to 10.5, all about a year ago. Running fine, until now. The power adapter has been funky for a while, bent connector and it has to be in exactly the right position to work, but always works. The battery (replaced once) doesn't hold a charge for long at all if unplugged.

Left it asleep, unplugged overnight, and now it won't turn on at all. Absolutely nothing happens when I push the power button. No fan or disk noises, no indication of anything going on. The battery was drained to one green light, but now shows all 4, and the green light is on around the adaptor.
I tried the PMU reset, and nothing.

Anybody have any wisdom here?

Thank you!

-tyler

Thanks Daniel and Ninja. Update:
I fiddled with the DC input by moving the adapter connector around, and it started up. So probably the adapter or the DC-in board, like you said...no?

Thanks again for the quick responses. Gonna try to squeeze a little more use out of the old girl!