Imagine booting up, logging on before your hair turns gray

— -- So long, Windows. Hello, productivity!

Booting up a computer can be maddeningly slow, and "reboots" even worse, as computer users stare at their monitors and wait seemingly forever to get back to work.

Several tech firms are aiming to solve this with "instant on" computing. Their software bypasses Microsoft Windows, the dominant operating system for PCs, at boot-up and goes straight to the Internet browser. There they run speedier and faster, akin to the experience seen on tiny netbooks such as the Asus EEE.

The players:

•Presto (prestomypc.com), a $19.95 software download launched Monday, brings the netbook experience to your notebook.

•Phoenix Technologies' HyperSpace (hyperspace.com), out since January, is also a software download, at $39.95 to $59.95 annually.

•Splashtop (splashtop.com), from DeviceVM, is bundled with new netbook computers from many vendors, including Asus, Hewlett-Packard and Lenovo.

•Always Innovating's Touch Book uses instant-on technology built into a $399 laptop that doubles as a tablet PC. It will be released in June.

The downside to instant-on computing: You can't open applications such as Quicken, Microsoft Word or iTunes. It's the Internet or nothing. "But you can do what most people care about," says Jordan Smith, product manager for Presto, from Canadian software firm Xandros. "Check your e-mail, do instant messaging, make Skype phone calls."

Phoenix CEO Woodson Hobbs says Microsoft msft has nothing to worry about in terms of the notebook and desktop markets. But for netbooks, he boasts, "We're going to completely displace Windows."

Well, maybe not anytime soon, if Microsoft has a say. The Windows software giant is at work on a new, leaner, lighter version of Windows, Windows 7, scheduled for release early next year.

With the release of its Vista operating system, Microsoft opened "a window of opportunity for a whole host of companies," says Roger Kay, an analyst at Endpoint Technologies. Vista is too big and takes too long to turn on and off, critics say. The new Windows aims to solve many Vista complaints.

Jay Paulus, a senior director at Microsoft, says Windows 7 tests are showing positive results. "We're seeing PCs go from cold boot to a ready desktop, where users can access their applications, at speeds comparable to 'instant-on' environments."

But competitors say that despite Microsoft's optimistic talk, the company won't be able to solve the basic problem: Windows will still be slower than computer users want it to be.

"A brand new Windows without any applications will load quickly, but as more and more applications are added, it will become slower and slower every day," says DeviceVM CEO Mark Lee. "That's just the nature of the beast."

Netbooks such as the Asus EEE run on Windows XP, the older version of Windows that is less complex than Vista. Microsoft says it is considering a Windows 7 "lite" version that will be able to run netbooks efficiently.

Overall, Paulus says, Windows offers consumers a "more familiar" and considerably "safer" experience because, with its size, Windows is constantly updating itself with new security measures.

The instant-on computing trend has its roots in Linux, the open-source alternative to Windows that has never taken off outside the hardcore geek community. Couple that with a new brand of smaller, cheaper computers that became really popular in 2008, and marketers saw an opening to bring Linux in a different name to a wider audience.

"People are afraid of Linux, but it's a wonderful alternative," says Smith.

"We have Linux under the hood, and it's an inexpensive way to get a computer that will bring you online quickly. We remove everything that's not necessary to do the most important tasks and end up with a faster-running computer."

Kay says the instant-on experience would appeal to pretty much all of the estimated 1 billion computer users, but "inertia is working against" the software. "Most (users) won't take the time to download it."

Still, he says that if even one-tenth of 1% of computer users do download a program such as HyperSpace, Phoenix could realize $12 million in sales.

"That's not a huge business but a nice start for a software company."