My sable will start then kill right away

Hello, i tried to install an auto start in a 96 mercury sable, everything went fine but when the car would start it would run for like 2 seconds then shut off. and the theft light would be on, so i finally removed the auto start and now it still does it with the key in the ignition. it looks like the computer has shut off the fuel supply or will not allow the car to start and stay running now. anyone know how to reset the computer or fix this problem? i tried disconnecting the battery and reconnecting it,
and that didnt work


Thanks