2001 Chevy Lumina security light?

I have a 2001 chevy lumina 3.1 liter miles 123400 I have owned the car since 2002 I was driving the car for about a hour I stopped to get dinner when I went to leave the car would not start it had been about 1 hour since I shut it off all lights worked the fuel pump was kicking on the raido worked the one thing I noticed was that the security light was flashing on and off but I never have had a alarm in the car the battery green light was showing also I unhooked the battery to try and reset the start that did not work also pulled the security fuse and that did not work please help. Thank you darryl