First check the battery. Get it load tested and be sure it has clean terminals. If it is serviceable have them check it and adjust when load testing.
Next clean the connectors and the opposite ends of the wires that connect to the battery. It should be at least one power and two grounds.
When you reconnect a battery be sure the connectors are shining and tight fitting.
If you turn the key, do you always, sometimes or never get the dash lights to light? Do you hear the fuel pump prime? It sounds like a little motor running and lasts a few seconds.
When you turn the key to start does the starter try to turn the engine or nothing? When doing this does the lights dim or the battery voltage dip heavily below 12V? Does the trip odometer reset?
After the battery and connections common failures that keep you from starting are bad starter, bad ignition switch and a bad crank position sensor.
Occasionally the neutral safety switch may be misaligned or bad.
Is the security alarm factory or after market?
Regards,
JPNinPA
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