Is there a problem with my battery or the camera?

I've had my Jazz HDV178 for over 2 years now, and I haven't used it in over a year because it stopped working all together. When I plug the camera into the original wall charger, the red light will flash not even 5 times and then stay lit. When I take the camera off the charger and try to turn it on, absolutely nothing happens. I've tried turning the camera on while it's still on the charger as well, but all I've gotten is the green light and the sound as if the power is turning on. The screen does not turn on when the camera is connected to the charger, and the camera does not turn on when it is not connected to a power source. I'm wondering if I need to replace the battery for the camera to work again, or if the camera has gone bad itself? I don't want to end up wasting my money on buying a replacement battery to find out that the camera is that actual problem.