I have a 2004 Buick Park Avenue. The key will not turn, tried the spare, no luck.
Tried moving the steering wheel, gear shift lever and pushed the brake peddle.
Is there anything other than the ignition switch that can cause the key not to turn.
This probably means you may have to replace the lock cylinder.
Try this suggestion, get some WD40 and spray a little into the key slot. The lubrication may unstick the tumblers inside and you may be able to use the key again.
Just a suggestion if it doesn't work then replace the lock cylinder.