Not turning over/BUZZING

91 Bronco 4.9 strait 6 5spd
Put new battery in and drove about a mile. Parked for 1 week and now this... Went to start it, and nothing,,, no lights or any thing. Figured battery died. Put charger on it and got a buzzing sound. Found that when I unhooked the battery, that the battery is fine. Sounds like rear of motor, maybe low. Thought it may be the starter fried... but then why is everything dead. Hard to ground? Why from sitting??? Is there any other ideas than the starter? Ok sound off.... Big thanks.... J

I would check for any burnt fusable links by the starter. Check by the solenoid for a burnt fusable link. I would move the seat back all the way and loosen the bolts where it bolts to the dash. The ignition switch sits just below the bracket you loosened bolts on. Look on ebay for a ford ignition switch so you know what you are looking for.
Use a 12volt test light to check for voltage going to the starter.
Unplug battery neg before replacing switch if it is the problem.