Car Will Not Start problems of the 1998 Buick Lesabre

I came home after bible study on Wednesday night and got up Thursday then the security light went blinking. My husband had the key ignition replace then brought new key but car still wouldn't start so had the car towed and repaired. 10 months and three weeks the car did the same but I was driving this time and it shut down in the road with me and my children. It was frighten but we made it safely out of the road before anything happen. I don't understand that this problem occurred again . I am upset about the problem. A car has no business shutting off in the road while a person is driving it accident or no accident because it in danger peoples life. A serious problem for many people whom have these cars made by gm.

I believe I have a problem with the vats . The system has failed preventing me from starting the car. I have checked the fuses and one was blown but that goes to the electronic level control (hence a second problem) itiallally the car failed to start after jiggling the key it started. The security light remained on the whole way home. Came home shut the car down and started back up again. Later that evening my wife took the car to the store, where it failed to start. She called me I promptly responded with 2 of my children in tow. After checking fuses, reading the owners manual and disconnecting the battery, jiggling the key the car started. . . Thank goodness. Then we got home and it died. Yesterday I checked all fuses to verify, its not that. . Finally determining its in the ignition system relating to the lock cylinder. I have an extended warranty and hope the dealer will fix it. Today I have continued to poke around and attempted to start it. . Successfully after jiggling the ignition/key. Do you know if this is a common problem for this vehicle? unfortunately we do not know if it will start again. This is not a pleasant situation. Do you know what might cause the lock cylinder to do this? will this require new passkeys?.