You mentioned that your Nikon D80 battery charged. You have a Nikon EN-EL3e, correct? Do you know what the voltage is on the battery after is has been fully charged and has sat untouched for 30min? The voltage on a 7.2v camera battery is in the low 8v range. You should be getting ~8.2v on a fully charged new battery. Since it's been 11 years, you should be reading a mid to low 7v range. If you are measuring mid to low 6v, your battery may not be in good enough shape to boot the camera. Is your battery a genuine Nikon battery or 3rd party? I've had a lot of 3rd party batteries die on me well before the genuine ones fail.
Good luck.