And then this year everything changed. Apple Computer, the maker of the Mac, switched to the same Intel-made processors for which Windows was designed. The new Intel-powered Macs, which began shipping in January, still come with Apple’s own operating system, Mac OS X, which is more modern and more secure than Windows XP. But these Macs can now easily run Windows too, and they run it as fast as standard Windows-equipped PCs.

Why does this matter? It means that you can switch from Windows to the Mac and still use the one or two Windows programs you require that have no Mac equivalent.

Among the Mac models that can perform this feat are the iMac and Mac Mini desktop computers and the MacBook and MacBook Pro laptops. Apple’s most powerful model, the PowerMac tower, is likely to be converted to the Intel chips by the end of the year, after which it, too, will be Windows-capable.

There are two options for running Windows on the Mac. They take different approaches, but in my tests, both have proved to be fast, stable and widely compatible with Windows software. One, from Apple itself, is free. The second, from a small Virginia company called Parallels, costs $79. But each carries an additional cost: You have to supply and install your own copy of Windows, which can run $200 or $300, depending on which version you choose.

The Apple system, Boot Camp, uses a technique called Dual-Boot. It splits your Mac’s hard disk into two sections, or partitions — one for the Mac operating system and all its programs and files, and one for Windows XP and all its programs and files. You can start, or “boot up,” the Mac in either operating system, but you can’t run both simultaneously. To switch between a Mac program and a Windows program, you have to reboot the computer.

The Parallels system, called Parallels Desktop for Mac, uses a technique called Virtualization. It creates a virtual Windows computer inside a window within the Mac operating system. Parallels runs Windows a tad more slowly than Apple’s Boot Camp, but allows you to run both operating systems, and compatible software, simultaneously. You can switch rapidly between the two environments without rebooting. I’m writing this paragraph on a MacBook Pro laptop, but I’m not using any Mac software to do so. Instead, I’m using the Windows version of Microsoft Word, which runs inside Parallels Desktop.

For this paragraph, I’ve switched back to the Mac side of the computer and am using the Mac version of Word. And I copied the previous paragraph from the Windows side and pasted it into the Mac document. It was fast and flawless.

Each approach has its strengths as well as weaknesses.

Apple’s Boot Camp turns the Mac into a true, no-compromises Windows PC-just like a Dell or Hewlett-Packard computer. When you boot up the Mac in Windows, no trace of the Mac operating system is running; Windows has all the hardware and all the memory to itself. In my tests, Macs running Windows under Boot Camp were wicked fast and handled every single program I tried, including Microsoft Office for Windows, the Internet Explorer Web browser and various games. The downside is that pesky need to reboot when switching operating systems.

Parallels Desktop is much faster than the old software for running Windows on pre-Intel Macs, a Microsoft product called Virtual PC. That’s because Parallels makes use of special virtualization features built into the Intel chips. And it has the great advantage of running Windows applications at the same time you are running your Mac programs. But while quite fast, Parallels can’t match the speed of Windows running under Boot Camp, because it must share hardware and memory with the Mac operating system. Also, Parallels won’t work with certain high-end Windows games, and it can have trouble recognizing some USB drives and CDs. In my own tests, Parallels did handle everything I threw at it, but I introduced only simple games. Everything ran as fast as it would on an average Windows PC, though not as fast as the programs ran under Boot Camp.

Because Windows is much less secure than Mac OS X, when you run Windows on a Mac, you have to take the same precautions you would with a standard Windows PC. That means you need to install and run both antivirus and antispyware software that is generally not needed under the Mac OS.

Apple’s approach is more secure than Parallels’s in this regard — with Apple’s Boot Camp, Windows can’t see or access your Mac folders or files. That means any malicious software running in Windows can’t erase or damage your Mac files. Parallels, on the other hand, optionally allows you to share folders between the two operating systems; if you enable this feature, you could give a malicious Windows program an opening to damage or spy on the files on the Mac side.

Installing both programs is fairly easy, but it’s a multistep process. With Apple’s system, you first download and install Boot Camp. Then, using Boot Camp, you divide your hard disk into Mac and Windows partitions. Next you create a CD to be used later, under Windows, to install software “drivers” that Windows will need to control all aspects of the Mac’s hardware. Then you install Windows. Finally, you install the CD you created.

Note that Boot Camp requires a full retail version of Windows XP, called “SP2.” You can’t use any other version of Windows, and you can’t use an upgrade edition, which requires an earlier version of Windows to be present on the machine.

Parallels allows you to install any version of Windows, even a very old one. But if you use Windows XP, you will in most cases also need a full, retail version, not an upgrade package. You first must buy and install the Parallels program, which creates an empty “virtual machine.” Then you install your copy of Windows inside Parallels. Finally, to enable certain key features, you have to install a program called Parallels Tools, which is included.

This all sounds harder than it is. In each case, the whole process took me about an hour and required no technical skill.

And it’s worth the effort. Boot Camp and Parallels have turned the Intel-based Macintosh into the only computer that can run nearly every popular software program, whether it was written for Windows or the Mac. On the same computer you can edit photos in Apple’s iPhoto program and check your e-mail in Microsoft’s Outlook — simultaneously, if you choose Parallels. Now, that’s progress.

Starting in January, six months earlier than promised, Apple began switching the Mac to the very latest Intel processors-allowing higher speeds at lower temperatures compared with the previous IBM chips. Apple’s sleek, slim computers can run faster without bulking up for extra fans or heat-dispersion space.

That change, in turn, enabled Apple to stun the world in April when it announced a free utility that permits the Intel-based Macs to run Windows as a complement to the Mac operating system. With this new software, called Boot Camp, a Mac user can start up the computer either as a Mac or as a Windows machine. That means people who resisted switching to the Mac because they need to run one or two programs available only in Windows can now convert without hesitation.

America’s slimmest brand-name desktop, the dazzling white iMac, now runs faster with Intel chips yet retains its slender form. So does the thin, aluminum-clad 15-inch MacBook Pro laptop, a renamed version of the PowerBook. Like its Mac siblings, the tiny Mac Mini desktop now includes an Intel processor that incorporates two “cores,” the equivalent of two processors in one.

These Intel models are Macs through and through because they still run Apple’s Mac OS X operating system, Tiger — which is so far ahead of Windows that it already contains the key features Microsoft is promising for its much-delayed new version of Windows, Vista, due in January.

But now Macs can run Windows as well. Apple’s other models should be converted to Intel by late 2006. They include the 17-inch-screen version of the MacBook Pro laptop, the thinnest and lightest portable available; the entry-level MacBook laptop, formerly called the iBook; and the top-of-the-line PowerMac towers.

The new Mac lineup doesn’t include some categories of computers offered by the likes of Dell and HP. For instance, Apple lacks an ultralight laptop like the 2.5- to 3.5-pound Windows models from Sony and Toshiba. It doesn’t offer gaming-specific desktop towers or big laptops, like those from Alienware and Dell. And it doesn’t offer models with built-in TV tuners and TiVo-like digital video recorders, like those available from most PC makers.

Also, while Macs now use standard ports and connectors, which can accommodate most any printer or scanner, they omit a couple of common features found on many Windows machines. They’re not equipped with readers for camera memory cards, and the laptops don’t have built-in receivers for the new, high-speed cell phone data networks. You can add both of these features as external add-ons, at extra cost.

On the other hand, Macs running the OS X operating system aren’t susceptible to the many thousands of viruses and spyware programs that plague Windows computers; most Mac users don’t bother to run antivirus and antispyware software.

Then there’s price. Years ago Macs cost much more than Windows PCs. That’s no longer true. The iMac is priced comparably to identically equipped Windows machines, though no similar Windows desktop is as slim. Mac laptops can run a few hundred dollars more than Windows models, though comparable Windows laptops tend to be thicker and heavier, with lower-quality screens.

But Apple has no offerings cheaper than its $599 base Mac Mini, which lacks a keyboard, monitor and mouse. It doesn’t play in the market’s bargain-basement segment, where Dell, HP and others have stripped-down models that sell for under $400.

Here’s a quick guide to the fresh Mac models, and to their new ability to run Windows.

DESKTOPS

The iMac. This is Apple’s flagship product, its main consumer desktop and, in my view, the best available consumer desktop. At first glance, it looks like just a sexy, white, flat-panel monitor. But there’s a powerful computer packed behind the screen, which can also run Windows. The iMac also has a built-in video and still camera, plus a special operating mode called Front Row that allows you to play music, videos, DVDs and photo slide shows from across a room, using an included remote control. The iMac starts at $1,299, complete with a built-in flat-panel screen.

The Mac Mini. The smallest desktop computer I’ve ever tested, at 6.5 inches square and 2 inches high. Yet it’s a full-fledged Mac, complete with the latest Intel chips, that can also run Windows. Starting at $599, the Mini includes Front Row with remote control and is often bought for connecting to a TV as a media hub.

The Power Mac. This is a heavy-duty tower, favored by graphic artists, musical composers, video producers and scientists. It has yet to be upgraded to Intel processors, but currently can be ordered with as many as four IBM G5 cores. For most consumers, it’s overkill. It starts at $1,999, without a monitor.

LAPTOPS

The MacBook Pro. Apple’s top laptop, a renamed, reengineered version of its famous PowerBook that looks and works pretty much the same-only faster. Though currently available only with a 15-inch screen, for $1,999, a 17-inch model may roll out. It’s not clear if the 12-inch PowerBook, which remains on sale at $1,499, will also be replaced.

The main difference between MacBook Pros and PowerBooks? The former use the new Intel processors, have built-in video cameras, and feature Front Row and the remote control. Oh, and they can run Windows. The MacBook.This is the rumored name for a new entry-level Intel-based laptop that will soon replace the iBook. It should be much faster and also be able to run Windows. Meanwhile, the iBook remains on sale, starting at $999. It uses the older IBM G4 processor.

WINDOWS ON A MAC

The new Intel-based Macs can run Windows via Boot Camp, a free Apple utility that overcomes some subtle hardware differences between the Intel-based Macs and standard Windows computers.

After you run Boot Camp, you simply buy a copy of Windows XP (Apple won’t sell or support Windows) and install it as you would on any regular Windows computer. You must use a full, nonupgrade copy of Windows that includes the update Microsoft calls “SP2.” These versions of Windows cost $200 to $300.

Once Windows is installed on a Mac, each time you start up you can choose whether to run the Mac OS or Windows. Only one operating system can be used at a time, and each controls its own walled-off section of the Mac’s hard disk.

In my tests, an Intel iMac running Windows performed like a fast, normal Windows computer and ran every Windows program and hardware device I threw at it.

Apple isn’t abandoning its operating system or switching to Windows. It’s making it easy to run Windows on a Mac in hopes of tempting potential switchers who would use the Mac OS most of the time, but need to shift to Windows periodically to run programs that don’t have Mac equivalents.

Macs aren’t for everyone. But they are superior computers, and with the new Intel chips and Windows capability, they are more attractive than ever.

Over the past few years, however, those extremes have begun to merge. Because of the spread of broadband Internet connections and improvements in cameras, software and computer processors, consumer videoconferencing has begun to look much better. It’s still not as good as expensive corporate linkups, but it’s finally usable.

As this affordable video technology has spread, online services offering video chatting have proliferated. Yahoo, AOL, MSN and Apple all offer videoconferencing. So do a host of less-well-known services, such as Paltalk, IVE and Skype. All are free or have free entry-level plans, but they still cost money to use. For one thing, you’ll need a broadband connection — on both sides of the conversation — to get the most out of them. And, of course, you’ll need a decent camera, with either a built-in or separate microphone.

I expect built-in cameras to become common in all but budget PCs in the next few years, but for now, they’re relatively rare — Sony has been building them into a few models for years, Apple included built-in cameras in its new iMac desktop and MacBook Pro laptop models, and some Hewlett-Packard laptops feature them as well. But most users will have to buy a camera. The biggest brand in add-ons is Logitech, and the best Logitech model I’ve seen is the Quickam Fusion, which sells for around $85 and works only on Windows PCs. The best bet for Mac users is an even better but costlier camera, the $150 iSight from Apple.

Both cameras attach to the top edge of your screen and deliver up to 30 frames of video a second, which is full motion to the human eye. Both include decent built-in mikes. And both also function as still cameras for snapshots. The Logitech has a higher resolution, 1.3 megapixels, while the Apple takes still pictures of under 1 megapixel.

One advantage of the Apple iSight, not surprisingly, is that it’s better integrated into the computer. No software need be installed; you just mount it atop the screen with an included clip or magnetic base, plug it into a FireWire port, and voil?†. In fact, it automatically launches Apple’s built-in videoconferencing program, iChat AV.

Like most Windows peripherals, the Logitech camera is a little trickier to hook up, but not by much. It does require a software installation. The camera plugs into any open USB port, though it needs a newer USB 2.0 connection for full frame rate.

Both cameras have a lens-blocking privacy mode, which allows you to avoid being seen during a video call or conference. Only your voice will be heard. But Logitech goes further — it includes an amusing software feature called Video Effects that permits you to disguise your appearance. You can add animated glasses, mustache, nose, hat and other features to your face. Or you can replace your image entirely with animated avatars of cartoon people and animals, including a dinosaur, a space alien, a cat, a dog or a unicorn. And while these visual effects aren’t exactly Hollywood quality, they do move with you as you speak, mimicking some of your visual expressions, like winking or raised eyebrows, and no special software or video service is needed at the other end of the conversation for your friends to see the special effects.

Once you have your camera/mike combination in place, you’re ready to roll. All you need do is pick your service, find some friends with a camera and mike, and you can start videoconferencing.

The daunting security problems that have plagued Windows have also prompted many of its users to take a serious look at the Mac. This trend has been further reinforced by the “iPod halo effect,” in which Windows users who own and love Apple’s iPod music players are willing to consider the company’s other products. As a result, Mac sales, while still relatively small, have been growing much faster than overall personal computer sales.

Are you among the PC majority considering a switch to the Mac? Then you probably have some important questions.

How do Macs compare in quality with Windows PCs?

I believe that, at the moment, Apple makes the best computers, and the best operating system, for mainstream consumers doing typical tasks — e-mail, Web surfing, office — productivity functions such as word processing and presentations, photo organizing and editing, playing and collecting music, and editing home video.

Of all the major computer makers, Apple is the most focused on consumers and small businesses. Most make the bulk of their money, and take most of their cues, from the information-technology departments of large corporations.

Apple’s iMac G5 consumer desktop is, in my opinion, the single best home computer on the market. Its PowerBook laptops are among the top portables.

Do Macs run Windows and Windows software?

No: Out of the box, Macintosh computers run only Apple’s own operating system, called OS X, and software written by Apple and other companies that is designed to run on OS X.

You can rig a Mac to run Windows and Windows programs by installing a special, $250 Microsoft program called Virtual PC, which creates a virtual Windows computer inside the Mac. But I don’t recommend this for frequent use, because the faux Windows computer it creates is relatively slow and is susceptible to the same viruses and spyware as a real Windows machine.

How does Mac software compare with Windows?

The Mac’s OS X operating system, the latest version of which is called Tiger, is far better than Microsoft’s aging Windows XP and already boasts many of the key features Microsoft plans to include in its 2006 version of Windows, called Vista. And the Mac comes with an excellent suite of free software that’s generally superior to comparable Windows programs that cost extra.

Out of the box, the Mac has better photo, music, video and DVD — creation software than any Windows computer I’ve seen. It has a better free email program and Web browser than Windows does, a better free word processor and much better search capabilities.

About the only software a typical consumer would have to buy for a new Mac is the Mac edition of Microsoft Office. It includes versions of Word, Excel and PowerPoint that are very similar to their Windows counterparts, and a program called Entourage that is different from Microsoft Outlook but performs the same functions.

Are Macs more secure than Windows PCs?

Yes. Since the OS X operating system came out in 2001, there has never been a report of a successful virus for it — that is, a virus that has infected numerous computers, and spread from computer to computer, outside of a lab. And there is little or no known spyware for the Mac. By contrast, there are tens of thousands of viruses for Windows and untold numbers of spyware programs. Just as regular Windows programs can’t run natively on a Mac, none of these malicious Windows-specific programs can run on a Mac either.

The Mac isn’t invulnerable, but it has better built-in security than Windows, and such a small market share that virus and spyware writers haven’t targeted it yet. As a result, most Mac users have been able to dispense with running the morass of security software that Windows users must employ.

Are Mac files compatible with Windows files?

Yes. Unlike older models, the current Macs have been specifically designed for compatibility with Windows PCs. The Mac OS and software can handle, without translation or conversion, all of the common types of files you use on a Windows PC. You can copy to a Mac all your pictures, MP3 music files, text files and Adobe PDF files, and they will open right up in Mac programs. There are also free Mac versions of the Real Player and Windows Media Player, and of Adobe Reader.

Microsoft Word files also can be opened, edited and created in Apple’s free, built-in text editor. And if you buy Microsoft Office for the Mac, all Office files, including Word files, Excel files and PowerPoint files, can be opened, edited and created on the Mac. Office files created on the Mac can be opened and edited in Windows Office, and vice versa.

Some specialized files created by particular programs, like database files or financial files, won’t be usable. For instance, the Mac version of Quicken is quite different from the Windows version and uses a different file format.

For occasional use of these programs, you can install Virtual PC.

In addition, nearly all keyboards, mice, monitors and printers made for Windows computers can be used with a Mac, if they connect via the industry-standard USB or FireWire ports. Macs can also share networks with Windows PCs and even look into the hard disks of Windows computers, and vice versa.

Is there anyone who shouldn’t consider a Mac?

Yes. Serious game players should stick with Windows PCs, which are much better game platforms and can run many more game titles. People who use specialized software or custom corporate software for which there isn’t a Mac equivalent should stick with Windows. While the Mac has rich offerings in mainstream software categories, it has only a fraction of the niche software and specialized business software that Windows does.

Also, you should stick with Windows if your home computer choices are dictated by your company’s IT department and the IT department is ignorant of or hostile to the Mac, as so many are. Although modern Macs are designed to access corporate Windows networks, and many do, if your IT department won’t help you with the transition, it’s not worth the headache to switch to the Mac.

Ten years ago, when Apple was stagnant and its products troubled, I recommended that consumers shun the Mac. If Apple’s quality and innovation slip, I might revert to that position. But for now, the Mac is the best computer, with the best operating system and the fewest security problems, for average consumers.