Redmond, Washington: Microsoft Corp founder Bill Gates said over the next two years he will ease out of a day-to-day role at the company he built into the world's biggest software maker.

His decision to step down immediately as chief software architect and to relinquish all managerial roles in July 2008 comes at a time when Microsoft, whose Windows operating system runs an estimated 90 per cent of the world's personal computers, is struggling to find new sources of growth.

Gates, 50, passed the technical mantle to Ray Ozzie, who joined Microsoft last year and is at the heart of Microsoft's push to maintain its dominance by transforming software into services that generate an ongoing stream of revenue instead of just a one-time sale.

By July 2008, Gates said, he will be working full-time for the Bill and Melinda Gates Foundation which he has funded with his software billions to promote health and education projects around the world but will still be working "part-time at Microsoft".

The world's richest man, whose wealth was estimated at $50 billion in March by Forbes magazine, will remain as Microsoft's chairman and an advisor on key development projects past the 2008 transition.

Milestones: Top of the Bill

  • Gates and his childhood friend Paul Allen founded Microsoft on April 4, 1975, in Albuquerque, New Mexico, to make and sell BASIC interpreters for the Altair 8800, an early computer that was sold to hobbyists.
  • Gates dropped out of Harvard University in his third year to focus on Microsoft.
  • In January 1979, the company moved from Albuquerque to Bellevue, Washington. It would later move to Redmond, Washington, where the company is now headquartered.
  • Forbes magazine has, for 12 consecutive years, named Gates as the world's richest person. In 1999, toward the end of the dot-com boom, Gates' holdings briefly topped $100 billion.
  • In the famous 1998 antitrust case United States vs. Microsoft, Gates during deposition testimony quibbled over the definitions of such words as "ask," "compete" and "we".
  • Gates was chief executive of Microsoft until 2000, when Steve Ballmer took that position. Gates has been chief software architect and chairman since.