Bill Gates, the man who started Microsoft and has been its public face throughout its three decades of existence, plans to step away from daily work at the company.

Gates announced on Thursday here that he will gradually relinquish his current role, ceding the chief software architect title immediately, while remaining a full-time employee for the next two years. In July 2008, he will remain as a part-time employee and chairman.

Gates' announcement comes as his company battles pressures on all fronts: a sagging stock price, competition from Google and nagging delays in the Vista operating system.

In a press conference after the stock markets had closed for regular trading, Gates announced that over the next two years he will gradually step away from his daily responsibilities at the company he co-founded some 30 years ago.

Microsoft's Chief Technical Officer Ray Ozzie will immediately assume the title of chief software architect, Gates said. In addition, Craig Mundie, CTO for advanced strategies and policy, will immediately take the new title of chief research and strategy officer and will assume Gates' responsibilities for the company's research and incubation efforts.

Gates said that he will work side-by-side with Ozzie throughout the transition period, but that a year from now, Ozzie and Mundie will begin reporting directly to Ballmer.

Gates explained that he has been working part time for the Bill & Melinda Gates Foundation and full time for a company that has made him the richest man in the world, and he wished to reverse those priorities.

"The road ahead for Microsoft is as bright as ever," Gates told reporters, noting that he plans to work full time through June 2007 and plans to remain as chairman for the foreseeable future. "So many seeds we have planted have just started to grow."

Gates said that his role has already changed significantly from the company's early days, when he liked to review each line of code and interview each job applicant. Although he said he likes to think he still has a significant impact on the broad range of company activities, he said that the products are already in others' hands.

"The world has had a tendency to focus a disproportionate amount of attention on me," Gates said.

Ballmer took the opportunity to characterise Gates' move as a broader shift for Microsoft, which has come under fire by some analysts, investors and employees for moving too slowly. "We're really also announcing the transition we are making as a company," Ballmer said. He pointed specifically to work the company is doing, led by Ozzie, to add services to everything it does, as well as a move beyond the PC into other devices such as mobile phones and televisions.

In the audience for Gates' press conference were many of the company's business and technical leaders including Ozzie, Mundie, retiring Windows chief Jim Allchin, incoming Windows chief Steven Sinofsky, as well as the three divisional presidents: Jeff Raikes, Kevin Johnson and Robbie Bach.

As for the company's stagnant stock price in recent years, he said, "Stock markets do what they do. That's their job."

Ballmer acknowledged that the company has "an opportunity to do better in some of the areas" in which it has products, but defended the company's overall record. "I think our company has performed very well," he said.

Gates shocked the technology world in 2000 with a surprise announcement that he would hand over the CEO role to Steve Ballmer but remain as chairman. At the time, Gates also took on a new role as chief software architect.

While Microsoft continues to perform well financially -- it pockets nearly US$1 billion per month on quarterly sales of about US$11 billion -- the company's growth prospects and ability to compete with a new breed of competitors has caused its stock price to stagnate. Shares closed at US$22.07 on Thursday in regular trading, down from a 52-week high of US$28.38. Shares have slipped steadily since trading at about US$35 in 2001.

Gates, 50, founded Microsoft in 1975 with high-school buddy Paul Allen to sell a version of the Basic programming language for the Altair computer. The company had considerable success in the 1980s, partly as a creator of software applications for Apple Computer's Macintosh computer.

But it was the company's decision to enter the operating system business that would propel it to the top of the technology world. The company's Windows OS runs on more than 90 percent of the world's PCs. The success briefly pushed Gates' net worth, largely through his Microsoft holdings, past US$100 billion in 1999. Gates currently holds about 977 million shares.

According to Forbes magazine, he is the richest person in the world with a net worth of US$50 billion in 2005.

"Gates certainly has been a driving force in the industry, for better and for worse. I think if you go back to 1981, few would have predicted the degree to which one OS would unite 95 percent of the PCs around the world," said Nathan Brookwood, an analyst with Insight 64.

"As Microsoft has grown, (Gates') ability to contribute at a technical level has become ever less critical to the company's success. I would suspect it won't be very different from a technical standpoint with him not involved on a full-time basis," Brookwood said.

"He was really the first technology-oriented entrepreneur who was also a great businessman," wrote Stephen Baker, an analyst with NPD Techworld, in an e-mail interview. "(He) kind of legitimised the idea that techies could make money and it was OK."

Gates put business success ahead of pure technology concerns when it came to his company, which probably accounts for some of the backlash against him and Microsoft from the technology community over the years, Baker wrote. "I think if you look at Google today, they are running into the same headwind, admired entrepreneurs doing good things technologically but now being challenged by needing to balance making money and building products."

CNET News.com's Scott Ard reported from San Francisco, and Ina Fried reported from Redmond, Wash.