I edited the thread subject to include the nature of the problem.
If the security light came on as Technical Ted indicated, then it is a VATS issue, meaning the car didn't sense the resistor pellet in your key was there. If this is the case, try cleaning the resistor contacts with rubbing alcohol. There are some ways people have suggested for cleaning the contacts inside the ignition tumbler, or you can bypass the VATS system altogether...try doing a search for VATS if this is your problem.
(edit) I found this thread; it might help some. http://www.bonnevilleclub.com/forum/...highlight=vats