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."

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.