COLUMBIA, S.C. — Nearly a year after he was laid off from his job as a window installer, Raymond Vaughn is still out of work, still scanning job listings on the computer and still sending résumés into a seemingly indifferent void.

But Mr. Vaughn now has another activity, one aimed at breaking free of his chronically meager financial straits: He is studying for a career in medical billing through an online course he found on the Internet.

For several hours each morning, Mr. Vaughn, 43, sits at a desk in the modest rented house he shares with his fiancée, memorizing medical procedures and absorbing detailed drawings of the human anatomy. “Medical terminology is kicking my butt,” he says.

He takes quizzes online, making progress toward the diploma that will, the school promises, set him up to work from home, processing bills for insurance companies while earning as much as $50,000 a year. “That sounded all right to me,” he says.