only if the loan is not satisfied. Sometimes you owe more than what your car is worth. Insurance company's only pay what the value is minus the deductible. This may leave a deficiency balance that has to be paid by you. If you don't pay the balance you will be in default of your loan.
Trading in a car does not affect your credit unless you sign a new car loan and get a new car. This may negatively or positively effect your credit.
In general, you cannot return a car to a dealer. You can sell it back to them, though. Selling it won't affect your credit.
It has the same effect on the credit.
Your credit can raise or lower your credit score. It is what consumer credit for buying a house or car is based on.
Any default on any loan will damage your credit in the future.
If the car was legally parked, Yes.
-Totaling your car and/or someone else's -Injury -Possible death
1 in 100
dude wheres my car
Bad credit will affect your APR on any new loan. Most banks use a tiered credit system to determine APR.