How do I reset the internal security system on my 1996 Olds 98 Regency Elite?

What is your question?

This is the first time this has occured. I was out for the day, and the car was running fine with no issues. I went into the store for 20 minutes, came out and the car wouldn't start. The radio and all stuff like that work, but the security light in the top right corner of the console is flashing. We tried turning the key to start and letting it sit for 15-20 minutes, but that didn't work. Is there other way to reset the system?