This is a notorious problem with the Saturns and well documented. they had bad problems with the key tumblers. Most times the tumbler needs to be changed. Its the pins inside sticking holding the key from inserting. you can try a can of lock lube bought at most parts stores.. Insert the straw end and spry some in the tumbler. Benin inserting the key in/out and it may then free up and slide in. Also can try tapping the face of the tumbler where key goes in with small hammer or equal and sometimes frees up sticking pins. if not.. then the tumbler will have to be changed Very common problem,
same thing as key will not insert. have seen this many times. here is a TSB
Bulletin No.: 06-02-35-016C
Date: October 02, 2007
Subject: Ignition Lock Cylinder is Hard to Turn or Binds (Clean and Lubricate Ignition Lock Cylinder/Housing) Models: 2005-2006 Chevrolet Equinox 2006 Pontiac Torrent 2003-2007 Saturn VUE
This bulletin is being revised to update the lubrication information by adding steps and photos. Please discard Corporate Bulletin Number 06-02-35-016B (Section 02 - Steering Wheel and Column).
Some customers may comment that the ignition lock cylinder intermittently sticks or binds.
A lack of lubrication may cause adjoining metal surfaces to wear, resulting in a significant amount of powder (black in color) to form in the ignition cylinder case housing.