By JOHN MARKOFF

Bill Gates, Microsoft’s chairman, is intent on performing what must be the world’s longest-running Cheshire Cat act.

Mr. Gates — who is reducing his role at Microsoft on July 1 and will work only on specific projects but will remain as chairman — appeared with his longtime friend and business partner Steve Ballmer on the opening night of the Wall Street Journal’s “D: All Things Digital” conference in Carlsbad, Calif.

During the 105-minute conversation, the two executives were most comfortable chatting about the past. They were cagey when it came to talking about the bid for Yahoo and what might happen next, and they were generally testy when they were challenged about whether Microsoft would continue to lag behind Apple in some areas.

The hosts of the conference, Walt Mossberg and Kara Swisher, tried several times to draw the two men out on the company’s failed effort to acquire Yahoo, but neither man was willing to say much beyond his previous public statements. Mr. Ballmer did reiterate that he reserved the right to reopen Microsoft’s bid in the future, but he was unwilling to talk about the circumstances under which that might occur.

Mr. Ballmer also repeated his recent statement that, having failed to see eye to eye on the price of the acquisition, the two companies are now talking about other unspecified partnerships.

Mr. Ballmer and Mr. Gates were much more willing to reminisce about their days as college students at Harvard. Mr. Ballmer also described how Mr. Gates attempted to recruit him to Microsoft while his former classmate was attending Stanford Business School and living in a “fleabag” apartment in Palo Alto.

Mr. Ballmer recalled that he had been reluctant, and that Mr. Gates had told him, “Too bad you don’t have a twin brother.” He said he called Mr. Gates back the next day and asked him if he would consider him for the job.

The joint interview took a slightly odd turn when, halfway through, the Microsoft executives consented to give the audience of computer industry executives a “sneak peek” of the next version of Microsoft’s operating system, known as Windows 7.

Although Windows 7 is not scheduled to ship until the end of 2009, Microsoft has been creating some consternation in the computer industry by talking about the new program as an opportunity to address some of the shortcomings of Windows Vista. On stage Tuesday evening, neither Mr. Gates nor Mr. Ballmer was willing to concede any major shortcomings in Vista. Mr. Ballmer said the company has shipped 150 million copies of the program, but he did acknowledge that Microsoft might have done some things differently “in hindsight.”

He blamed compatibility issues that have led to criticism of the program on the company’s decision to focus on computer security problems.

During the brief onstage demo of Windows 7, a Microsoft software designer made the puzzling choice to unveil a new “multitouch” feature by working with a paint program, evoking memories of the original Macintosh paint program in 1984. She then used the touch-sensitive technology with a photo collection and a mapping program, evoking comparisons to both the iPhone and Google Maps, which already have similar capabilities. (You can watch a video of the multitouch feature on the Microsoft Vista blog.)

Another new feature appeared to be a circular pop-up menu that provided a “concierge” function.

Fencing over the issue of whether Apple will get to market first with desktop multi-touch features, Mr. Ballmer implied that the two companies don’t compete directly.

“We’ll sell 290 million PCs, and Apple will sell 10 million PCs,” he said. “They’re fantastically successful and so are we and our partners. But it’s a different job. Steve can flip his hand and sell a few models and I don’t take a thing away from him.”

In response to a question from the audience, Mr. Ballmer insisted that Microsoft had not been damaged as a brand or in its strategy by its failure to acquire Yahoo.

“The world recognizes even greater seriousness than when we started,” he said. “It’s certainly something we thought about before we put in the bid because there was no guarantee.”

Mr. Gates was the less vocal of the the company’s two largest individual shareholders, but he did show animation at various points during the evening. Asked if he saw himself as a businessman, Mr. Gates responded, “Sure, sales minus costs equal profits. Is there more?”

In response to a question asked by Tim O’Reilly, the computer book publisher and conference impresario, about whether Microsoft had a “big hairy audacious goal,” in the tradition of its original commitment to put a personal computer on every desk and in every home in America, Mr. Ballmer and Mr. Gates suggested that the company now had many big goals, but not a single overarching goal.

The industry commentator and investor Esther Dyson suggested that the company did need a single goal, like transforming the nation’s health care system.

Mr Ballmer responded that he wasn’t sure that tackling problems where software wasn’t fundamental to the solution was appropriate for Microsoft.