Original Thread (http://www.automotiveforums.com/vbulletin/showthread.php?t=367890)
I have a 97 Riviera with all the same symptons. The common feature seems to be the security light coming on when attempting to start car. I have tried all combinations of entry to the car and order of steps up to turning the ignition key. When this happens, there is no alternative but to wait until the secuity feature times out. This car has almost 300,000km and has displayed this problem for over a year. I am inclinded to think that it's the contacts within the switch... which upon failing to pass the current through the key, triggers the security unit to perform what it's supposed to do - to immobilize the car.... certainly it does this!

Let's start with the simple things first. Do you have another key to try, or have you cleaned the resistor on the existing key?