My 2003 Buick Lesabre special edition won't start.

Have had problems starting my car.  Replaced the
battery, the starter. Security light flashes and it
doesn't turn over but makes the noise like clicking.
All dash lights go on. I've figured it out. I have the
car turned off with keys in the ignition. I hit the trunk
open button on the drivers door to open the trunk.
Put stuff in trunk and close the trunk then car door.
It doesn't start every time. Take the keys out of
ignition and relax. So have to wait about fifteen
minutes and it will start. At least with my car this
works. So now I don't panic. It's a security problem.