Bad Battery or bad Opti?
 

Car radio and lights turn on but the car just clicks when I try and start...

Also looking up an Opti-Spark at auto-zone but can't find it

Sounds like a dead battery. If the opti was bad, the engine would still crank.

I just recently had the same problem.

I thought it was a dead battery that was REALLY dead since it wouldn't even hold a charge...

But it was really just a loose battery cable (which meant the funtion missing was the battery).

My guess is the battery.

Thanks guys, I tried charging the battery but it was so dead it wouldnt even do that... had to buy a new one.

Now my question is how does a battery that's showing +18 on the meter during driving, go from being good at 2am to dead and won't charge 10 hours later?? I mean if it shorted, it would have blown the electronics in the car or atleast not been able to turn the CD player, lights, etc on. If it wasn't being charged or the lights had been left on I could understand... any ideas?

Bateries just some times go out, I had a starter, worked perfect, started the car up to move it, not but 5 minutes later went to start it and it was dead as a door nail.

Did you have your old batery tested?

Sometimes batteries do just crap out like that. One cause sometimes is if you have a cracked plate or a cracked post on the battery. All it takes is a little bump and then the battery is gone because is either shorts out or creates an open circuit then the plates/posts separate. Another reason is low electrolyte (water) in the battery.