1992 Pontiac Bonneville Won't Crank

My problem is intermittent. It has not started cold, hot, warm. It may start repeatedly for days, and you try the next time and it won't start. So far it has always started again, maybe an hour or more later. There's power to lights, fuel pump, blower, windows, etc. but engine will not crank. No click, no noise. During a period when the car would not start, I ran a wire from the selonoid to the battery, and with the ignition switch on the engine started but immediately shut down. With the ignition switch off the engine just turns over. I'm wondering about the securuty system. Need help.