OT: Car won't start. Battery? Starter?

[davester]

If it was the battery or corroded battery terminals, the interior lights would dim when the clickety click sound occurred. If they are unaffected then it is another problem. It could be a bad engine ground, or bad starter connections but then the starter would have slowed down. The clickety click sound is almost certainly the solenoid. So, you probably have a bad solenoid.