Nikon D5000 won't turn on with full battery. NOT A RECALL?

I've had this camera since June 21st, 2010 and it has always worked absolutely FINE. No problems, glitches, or anything. I charged my battery and put it in the camera the correct way and it will not turn on. Seeing that it has been working for months, it is not a recall. (It is not a used camera. I bought it new.) Is there some kind of reset? Do I need a new battery? Help!

Added (1). The factory reset DOESN'T WORK.

Added (2). The battery goes on the charger, not the camera. I couldn't have killed the camera. So is it the battery? If so how much do new batteries cost?

You probably need a new battery or you put the camera on the charger so long that the camera can't turn on.

Just call Nikon. They will help you.

800.NIKON-UX

There's a reset. It is called a two button reset and there are green dots next to the buttons.

This is in your user manual

Note: Your Li-ion battery should last at least five years if you treat it properly

Bring your camera to the store you bought it from. See if you can have them lend you a working battery to test. If your camera works, buy a new battery. If it doesn't, ask them how you can have your camera repaired. Remind them you bought the camera from them.