Windows users have raised concerns about Microsoft's new licensing system for Windows Vista, which will allow them to transfer a Vista license to only one machine other than the computer for which it was purchased.

The licensing scheme will also impact against users wishing to run Windows now and then on a Mac, using Boot Camp.

The new licensing has caused confusion, especially for users who rebuild computers with new components several times a year, or who plan to upgrade their computers more than once in the lifetime of the operating system. Users are demanding clarification from Microsoft about how scenarios like these will work.

"My question about the one time transfer is what constitutes a machine?" asked Windows user Roger Halstead. "I have four machines and they are running legal copies of XP Pro. Those four machines are in a constant state of upgrade. I have to reactivate the operating system around three or four times a year due to upgrades."

Halstead said that if he is not allowed to continuously upgrade his machine without purchasing new licenses, then "Vista will not be a viable operating system for me."

"I can stay on XP Pro, which I probably will as long as I can, but what happens when MS no longer supports XP?" he asked. "If I have to do a reinstall, will I be able to get it to work?" So far, Microsoft has not responded to these kinds of questions.

Don Smutny, a software developer for DST Systems, said: "If someone could come up with a Linux distribution that was just as easy to use as XP and included Windows emulation software that would allow users to play their Windows-based games without a large performance hit, then you will finally see the shift of operating system use that the Linux folks have been saying is 'coming soon' for the last ten years," Smutny said.

He's not the only user who is downright angry with Microsoft for its new licensing practice. Another Windows user, Mark Smith, who has his own business developing custom data-acquistiion and analysis packages for industrial applications, said it shows how "arrogant" Microsoft has become.

"It knows that governments (both the US and EU) are essentially powerless to effect any changes to the Microsoft status quo," he said. "It also knows there are no real competitors (Apple and Linux notwithstanding). So it's new attitude is to hell with the customer, we're going to do whatever we want because the customer has no choice but to buy Vista."

Like Smutny, Smith added that he, too, has been on the lookout for years for a viable alternative to Windows so he does not have to do business with Microsoft.

"I've tried all the competitors and hoped that IBM would have stuck it out and created a viable competitor; they were close," he said. "There certainly is a huge market, so we can always hope."