The contrast with this week's Comdex keynote, the 20th by Mr Gates, is striking. The dodgy slides have long since given way to a slick presentation, complete with a now traditional video interlude in which Mr Gates and his second in command, Steve Ballmer, send themselves up in the style of a recent Hollywood blockbuster.

Windows, just a prototype in 1983, is now the dominant personal-computer (PC) operating system, having seen off a host of rivals. The computer industry has mushroomed in size, gone through several booms and busts, and is now worth around $870 billion. Microsoft has become the world's largest software firm, and Mr Gates the world's richest man. His firm has also, of course, been through a bruising battle with antitrust regulators. But even as the landscape has changed around Mr Gates, his position as the industry's figurehead has remained unchallenged. Each year, for two digital decades, he has returned to Comdex to rally the industry, hold court with analysts and journalists, unveil new products and present his optimistic vision of the future.

Yet this year the mood at the show was unusually gloomy. There was much muttering about the sparsity of both exhibitors and attendees, whose numbers fell to around 50,000 this year from around 200,000 in 2000. Having given his speech in the spacious MGM Grand Garden Arena for years, Mr Gates was this year back in the familiar surroundings of the Aladdin theatre, which holds 7,000 people, half as many as attended the keynote at the height of the boom. Veterans grumbled that a once-sprawling show that used to take five full days to absorb could now be covered in an hour or two. Once the biggest annual show in Las Vegas, Comdex has lately been eclipsed by the Consumer Electronics Show (CES), which earlier this year attracted around 120,000 visitors. This mirrors the shift in the technology industry's centre of gravity, away from PCs towards sexier consumer-electronics devices such as mobile phones, games consoles, digital-video recorders and flat-panel TVs.

Microsoft faces the same challenge: its dominance in PC operating systems and office productivity software leaves little scope for growth, forcing it to look to new consumer markets. Tellingly, the firm now exhibits both at Comdex and CES. But although it is one of the titans of the computer industry, Microsoft has far less clout in the world of consumer electronics. Its smartphone software has been slow to gain adoption, its Xbox game console lags far behind the Sony's PlayStation 2 and its software for TV set-top boxes failed to gain much traction. Mr Gates's latest toy is a watch with a built-in radio, capable of receiving news updates, stock quotes, weather and traffic reports and instant messages. But after repeated delays, it has yet to go on sale, and it is difficult to imagine that it will create a big new market.

By referring back to his first Comdex speech in 1983, however, Mr Gates reminded his audience just how long (by the standards of the industry) he and his firm have been around, and how willing he is to play a long game. Microsoft's gradual establishment of its dominance in PC software, via its Windows and Office monopolies, owes as much to its ability to outlast its competitors as to clever programming or anti-competitive behaviour. Microsoft's deep experience of the computer industry means it knows what all the mistakes are, and what traps and pitfalls to avoid.

The trouble is, that experience, like the Windows monopoly, carries little weight in the consumer-electronics business. And in this new arena, Microsoft faces its two most daunting foes so far: Nokia, the world's largest handset maker, in pocket-sized mobile devices; and Sony in living-room consumer electronics. Both rivals have demonstrated their ability to borrow from Microsoft's own playbook. Nokia is off to a flying start in establishing its Series 60 software as the Windows of the pocket; and Sony's dominant PlayStation console technology, which it is now combining with other devices such as DVD players and satellite-TV tuners, is the nearest thing to Windows for the living-room.

But, judging by the long view described by Mr Gates, it is still relatively early days for Microsoft's consumer-electronics ambitions, and there are one or two hopeful signs. Motorola and Samsung, the second- and third-biggest mobile handset makers, have both announced phones based on Microsoft's smartphone software. Microsoft always regarded the Xbox as a trial run; it is now getting ready for the battle between Xbox2 and PlayStation 3, likely to start in 2005. And its new hybrid internet-TV technology, IPTV, is generating much interest.

Of more concern is that, back on home turf, Microsoft faces another worrying threat: the many security vulnerabilities of its own products. In his speech, Mr Gates said that closing loopholes exploited by viruses, worms and hackers was “the largest thing we are doing”. Rather than unveiling a clever new PC or mobile device, his first demonstration was of a piece of software that simplifies the management and installation of security patches, followed by a demo of a new kind of firewall and the announcement of new spam-filtering software.

Hardly thrilling stuff. But Mr Gates subtly reminded his audience that, for all his firm's woes, he has seen off many seemingly invincible rivals. Only a fool would suggest, as the industry shifts again, that he might not do so once more.