The one thing we can say with certainty about the future is that it will surprise us. But we're in a curious time in computing, when the assumption seems to be that everything will stay the same. Take today's trends and stretch them out a bit to see what the future looks like.

By that logic, computers will just keep getting faster and cheaper, and we'll all be running some future version of Microsoft Windows that uses menus and mice, just like now. But what if the future is more interesting than that?

What if hardware breaks in a new direction, and software is no longer tied to specific operating systems like Windows?

That's the promise of a new Intel chip design, one that may turn all our PC assumptions on their heads. Within about five years, you should be able to buy a machine that can run several different operating systems simultaneously.

Maybe there's a great Mac browser you favor, but you also need Microsoft's ActiveSync to keep up with your PocketPC.

No need to chose between them with the new technology, which Intel has code-named Vanderpool. You could be running Red Hat Linux, Microsoft's upcoming Longhorn version of Windows, and Apple's latest software with the same ease you run several programs at once now. The software and hardware manufacturers will no longer be able to lock in their audience, and the range of consumer choice will multiply.

Yes, there are ways of moving between operating systems today, but they're clumsy and work through software only. One way is to set up a dual-boot system, where you make a choice every time you turn the computer on. A PC owner is limited to Windows and Linux when doing this, and there is a long reboot needed to move from one system to the other.

Some Linux versions, as we saw last week, are beginning to offer limited compatibility with Windows programs. And there is a broader range of "virtualization" software that creates "virtual machines" -- PCs in software that can run several operating systems at once on the same box. The best of these is VMware, but Microsoft has just finished a new version of its own Virtual PC for Windows.

The broader vision these companies are embracing is "utility computing," an attempt by big players such as IBM and Sun Microsystems to make hardware that can adjust to changing conditions and reconfigure itself as needed. One way to do that is to collect computing power from many different sources and supply it to the job at hand, a method similar to how utility companies manage power.

Intel's Vanderpool chip will make the job of virtualization software much easier. One chip will be able to function as several chips, with virtual PCs inside the processor. That means some of the benefits of utility computing are headed for the consumer.

The long-haul view is this: As business adapts to new computing models, tapping into grids of processing power, the importance of a monolithic operating system will vanish. Windows rules the roost now because so many programs run on it. But there will be no compelling reason to standardize on one system when PCs can be fine-tuned to run whichever application is most needed.

Windows users will begin to experience the freedom to try out software written for Linux and, depending on what Apple does, the Mac. Imagine having a single machine that can run any program you choose, with no need to re-boot to move between these environments. Tying programs to specific operating systems will no longer be possible, and the era of the truly customized computer will have arrived.