Something is WRONG. You can't register a car in Virginia without titling it in Virginia. If he has a Virginia registration, he should have a Virginia title. I'm having my doubts that he is giving you valid title. Normally, if it hadn't had Virginia plates, it would be straight forward, you bring a bill of sale and the out of state title signed over and proof of emissions inspection (if you're in one of the Northern Virginia counties or independent cities) to the DMV and get it issued.