1991 Cadillac Fleetwood wont start

1991 Cadillac Fleetwood V8 Two Wheel Drive 125000 miles

My car won't start. The belts and pully's turn and the electrical is on in the car. My battery went dead and prevented my car from starting. Battery checked and was dead. Got a new one and does the same thing. Belt turns but just doesnt kick over. Had my alternator checked and also good. About two years ago, also had fuel pump, fuel filter and starter replaced. If I keep the key turned the belts and pullys keep on going. Thats it.