I drove my Civic last night delivering pizzas in a massive rain storm. It ran fine and it started fine after work when I went to the store. But, this morning it wouldn't start and it won't even try to turn over. And I'm pretty darn sure it is not an electrical problem... all the lights and what not are fine. When I try to start it, it makes a very short and very soft thud(or maybe hum), and then does absolutely nothing. I'm just wondering if maybe something got wet and won't allow it to start. I drove through some deep water, but it was running fine after that and it restarted several times after the rain. Could it maybe even be my starter? Any help would be greatly appreciated.

Things to consider:

1. Make sure your battery is fully charged.
2. Clean battery terminals and connectors.
3. Remove negative. Battery terminal and clean starter/solenoid terminals.
4. Check alternator.
5. Check starter.
6. Check under-hood and under-dash fuses with a test light or multimeter.

Possibly, your battery has been marginal before and, with the drop in temperatures the past few day, your battery died. Colder weather is always a test for whether a battery is really any good or not.

My battery is very new and this just doesn't seem like a power problem to me. I had trouble with my ground a while back and it isn't acting anything like it did then. I checked that to though. Is there any chance of this having something to do with the switch on my clutch?

There is an interlock switch, so the engine can only start if the clutch is depressed. I could be out of adjustment, but it is a long shot.

Power, most likely, is not getting to the starter solenoid. If it was, you would at least hear the solenoid click. Have someone start checking for power at the solenoid.

Well, now I'm a little confused. I just came home for a late lunch and my car started right up. I'm guessing something had gotten wet and apparently dried out? I'm glad it started, but I sure would like to know what happened this morning. Thanks for your help txgreasemonkey!:D

Sounds like a grounding or corrosion issue. Clean terminals, grounds, and apply silicone dielectric grease. If you don't do anything else, at least spray the main ground, battery connections, and solenoid terminals with WD-40.

For anyone with the same problem, it turned out to be a bad solenoid on the starter. It would work on and off and finally gave out completely.