My Civic is broken down, and I'd like to get an idea of what *could* be wrong with it to decrease the likelyhood I'll get ripped off.The car won't start - it does not even attempt to turn over; just clicks when I turn the key. The check-engine light is not on, the oil has recently been changed, I had a tune-up and got a new battery about a year ago.The only thing wrong with it was the exhaust - it had started running loud about 80 miles ago (probably less).Can you give me a best and worst case scenero for what could be wrong?