1998 olds Achieva not getting fuel, security light flashes

Hi
I recently bought a 1998 Olds Achieva. It ran fine on the way home. Then I shut the car off and tried to start it again and it would not start. It runs for maybe 2-5 seconds then just stalls out like it is not getting enough fuel. The security light keeps flashing and we tried the 10 minute fix and this did not work. So we changed the fuel pump and a few other things and that did not fix the problem. Do you think this has something to do with that friggin security system that they put in these cars? Now we are thinking about changing the crank censor. Could this be the prolem. Like I said we tried the 10 minute fix, where you turn the key on and leave it on for 10 minutes then shut the key off and try to start the car. It still stalls out after 2-5 seconds of starting. Oh we even put n a different key switch and had the original key for the new key switch. Any idea what the problem could be? I have put to much money in to this car already and can not take it to the shop.