If the engine is spinning but not starting then we're in a completely different universe. Forget about the inhibitor and battery cables, etc. The ignition switch could still be bad, but so could a hundred other items, at this point. I wish I could be of more help, but once the engine actually spins it becomes a whole new ball game.
Good Luck! If you have more questions feel free to ask, I should be home for most of the day tomorrow, I've gotta have a test at the hospital and I'm supposed to be woozy for most of the day - can anyone tell the difference?
