[HUMTECH]

Well sounds like the lock cylinder has fallen apart, does it feel rough when you put the key in? You can try to force it to turn. Put the key in and if I remember right should be able to get vice grips on outside edge of cylinder. Get them real tight and try to force it to rotate. Or cut a v notch in end of cylinder and use a chisel and hammer to try and force it around. If it goes then you will be able to remove ignition cylinder from housing and get a new one. Any gm dealer can supply and code a new one for you so original keys will work.