2001 Pontiac Bonneville Won't start

This car sits for days at a time without being started. Recently the battery went dead after sitting for about two weeks. I charged the battery up with a slow charge, and it started. Then it sat for a week, and battery went dead again. This time I charged the battery up, slowly, and the car wouldn't crank. All the electrical seemed fine otherwise. I removed a number of fuses to check them, and also removed the relays that were associated with the ignition system to reseat them. Now there is no electrical at all, no interior, exterior lights, nothing. The electrical is completely dead. What's going on?