Macbook won't turn on after battery dying.

2 days ago, I was using my macbook ('09) without it plugged in. The battery didn't die while I was using it, but I didn't plug it back in when I was done, so it died overnight. We lost electric that night so it went over 24 hours with the battery being completely dead. Now I have it plugged into the charger, but it isn't turning all the way on. It's been plugged in for about an hour now; is it possible the battery is just taking awhile to charge and power up? The light at the bottom is turned on like it's on and the fan is running (very loudly, much louder than normal), but the screen is black and won't do anything.