unfortunately it sounds as thought you've been screwed. my best guess is that you either just bought a stolen car, or you bought a vehicle that was pieced together from scrap parts or a totaled vehicle. to properly buy a vehicle from a private dealer that dealer must hand over the title to you, only after signing the portion of the title that implies directly to selling the vehicle. once that title has been signed by the previous owner you must bring that title to your local state DMV and apply for a new title that will be listed under your name. without a title, and without said title being signed you do not own anything.