1. Obtain the following documentation:
* A bill of sale from the auction where you purchased the car, clearly showing the purchase price and the date of the sale.
* A completed Affidavit of Sale form (provided by the DMV) that confirms the sale and affirms that there is no lien on the vehicle.
* Proof of insurance for the car.
* A state-issued photo ID.
* Pass the emissions inspection if required by your state.
2. Visit your local department of motor vehicles (DMV) office and submit the documents mentioned above.
3. Pay any taxes and fees associated with vehicle registration as the lien is already satisfied when the auction has happened.
4. The DMV will verify the information and issue you a new registration and title with your name as the owner.
If you're attempting to register a vehicle with other issues like a salvaged title or a vehicle that has not passed an inspection, additional documentation and inspections might be necessary. Consult your local DMV or use their website to access information and specific instructions for your state's registration requirements.