Power on, standby light on, Charger connected, but No Boot Up?

Recently, the battery in my PowerBook G4 15" seemed to be acting as if I would need to replace it soon. I ran the battery updater, however, I got a warning screen. The Charger is recently new and has the "yellow" and "green" lights. I noticed that every now and then it would go yellow, as if to be charging, but the battery icon would soon change to 0% and the charger light would revert to green. Knowing the PB is going on 5 years of age, I figured a new battery was a must.

Here's my issue.

Now the laptop will act as if to be ready for powering on, but that's as far as it gets. The charger light is green, the power button is pressed, the cd-rom device will make it's notable warmup buzz and clicks, there is a slight hum from what I can assume is the hard drive turning, and the standby light will become constantly illuminated.... and that's it.

No typical boot up chime/chord, the monitor doesn't light up, the apple on the back isn't lit (I know if the monitor is blank, it should be too, but still), and I'm stumped.

I read questions saying there is no power; or there is boot up but no picture; or they have other problems... but this is just a half power up with no boot up or picture.

Thank you for any advice and knowledge that you can spare for me. I love this Mac, it was the last Christmas gift I received from my Grandmother before she passed, and we shared so many special memories, some of which I had yet to finish backing up.