Security is on the cars turns on and it shuts.

Your VATS (Vehicle Anti Theft System) is engaged. If you have a spare key try that. If not or it don't work, try bypassing the VATS system. To do this you need to check the resistance of your key and then but a resistor from a place like radio shack that matches your keys resistance. Then look under your steering column area and find an orange wire. There should be a connector there. You need to cut that and install the resistor in between. There's plenty of video;s on youtube you can find that show you how. Once you do that your car should run. Only bad thing is, your making your car easier for car thieves to steal but itll run. ;P