Michael Saul Dell (1965-) joined the University of Texas at Austin with the intention of becoming a physician. While studying there, he started a computer company in his dormitory, calling it PC's Limited. By the time he turned 19, it had notched up enough success to prompt Dell to dropout.

In 1987, PC's Limited changed its name to Dell Computer Corporation. By 2003, Dell, Inc. was the world's most profitable PC manufacturer.

Dell has won more than his fair share of accolades, including Man of the Year from PC Magazine and CEO of the Year from Financial World.

His personal net worth is estimated at $16.4 billion.

Image: Michael Dell, chief executive of Dell Computers. | Photograph: Mark Ralston/AFP/Getty Images