Can anyone help with an ignition key that won't turn in a 01 Olds Aurora?

Ignition key won't turn in 2001 Olds Aurora. Other keys also don't turn. Turning wheel while turning key doesn't work. Key releases fine. Electrical power seems ok. Ignition switch is on dash not on steering column. Automatic transmission shifter is between seats and locked in park position. Any suggestions greatly appreciated.|||Fuse? or Mechanical Link to brake pedal.