1999 Oldsmobile Bravada ignition is stuck

This morning I went to start the bravada and after i turned it over nothing happened and the key became stuck. I had no power so i figured the batt was bad. I took it in and bought a new one, brought it home ,hooked up the batt. and the power flickered on for a second and it released the key. i put the key back in and it locked up again. i dissconnected the batt. and tried again but the key remains stuck, i cant shift out of P, and there is a strange noise comming from the relay box under the hood. what i thought was gonna be a easy fix is turning out to be a real pain in the ass. any suggestions would be greatly appreaciated.