You can get a car loan, but will have to put down a very hefty down payment - sometimes as much as 50% of the value of the car. Small finance companies are more likely to help you out with that, but...
If you did not buy the car it depends on the creditor. Some will void out the loan, others will not. If they do not void it then you have all the money from the loan... so you can pay the loan in...
You will still owe the money back with agreed upon interest. There may be some legal issues if you used the car for collateral and you do not own the car. return the money with the interest. the...
As long as you have enough credit available yes. Just remember even if the payment is from another source, you are responsible and it eats into your available credit until it is gone.