If the engine won't turn over at all chances are you have a bad starter, or starter solenoid. Coil packs would not even be an issue here. There is about a 1% chance it would be a bad wire going to the starter but I wouldn't even consider it before trying a starter.
If you own a test light you can try this easy test first...
- Locate the starter/solenoid assembly
- Locate the big stud with the power wire coming from the battery hooked to it
- Hook the ground of the test light to a good known ground (beware on this one, more than one experienced mechanic has been fooled by it... rusted/corroded metal is not a good ground by any means...) (Trick of the trade, clamp a pair of Vise-Grip pliers to a piece of metal (unpainted) on the engine, or the body and wiggle the pliers around a bit, this gets rid of corrosion and creates a good ground, clamp the ground wire from the test light to the handle of the pliers)
-Check to see it you have constant power (test light lights up when you touch the big stud on the starter with the probe of the test light)
-Next locate where the smaller wire hooks to the starter solenoid (usually right next to the big stud)
-Put the probe of the test light on this smaller stud
-Get someone to turn the key like they would start the vehicle and verify that you have power on the smaller stud
If you have power on both, the starter motor or solenoid are bad (sold as an assembly), if not, you have eith a problem with the ignition switch, or wiring.
Here is the image of the starter, the big stud i'm talking about is right on top, (the one under it is the stud with a permanent wire running to the motor), and the smaller one is right under it (between the 2 main studs of the solenoid)