Microsoft's (MSFT -1.96%) release of its new Windows 10 operating system may be one of the most pivotal moments in the company's history.

The new OS follows Windows 8, a bold, but failed attempt to reinvent how people interact with their PCs. Windows 8 was bet that touchscreens were going to take over. It jettisoned many familiar features from Windows, including the traditional start screen and menu in favor of an icon-based interface.

It was an idea that, if you view it positively, was ahead of its time. Though people are comfortable using an Apple (AAPL -2.19%) iPad-like interface on tablets, they weren't ready to do so on non-touch desktops and laptops. That left Microsoft with an OS optimized for an audience which really did not exist yet and a customer base using a product that was less than intuitive.

To fix those problems and essentially reboot the Windows brand, Microsoft skipped Windows 9 entirely and went right to 10. That OS has been publicly available through a beta preview for months, but the company had not announced when the release version would be made available. That has changed as Microsoft used its Cortana voice assistant to deliver the news.

"Windows 10 will be available on July 29, but you can reserve a copy now. Can't wait to be on your PC," was the message delivered by the assistant, which is a key part of the new OS. 

Microsoft posted the Cortana recording on Soundcloud. Source: Microsoft

What happens on July 29?
The PC and tablet version of the OS will go on sale, according to a Microsoft blog post by Windows executive Terry Myerson. The release date for the phone version has not been released yet.

On July 29 any user with either Windows 7 or 8 will be able to upgrade for free. "If you purchase a new Windows 8.1 device between now and then, the Windows 10 upgrade will be available to you and many retail stores will upgrade your new device for you," Myerson wrote.

Anyone with a version of the OS older than Windows 7 will have to pay in order to upgrade. Microsoft has not released pricing for customers moving from older versions of its operating system. 

Myerson explain how the upgrade process will work for Windows 7 and 8 users.

The Windows 10 upgrade is designed to be compatible with your current Windows device and applications*. We are hard at work to make this upgrade process a great experience. You can reserve your free Windows 10 upgrade now through a simple reservation process. Look for this icon in your system tray at the bottom of your screen, simply click on the icon, and then complete the reservation process.

Making a reservation allows the company to send you pieces of the new system in advance in order to ease the process on July 29. People without reservations can still upgrade, but it may take them longer depending upon demand. Reservations for Windows 10 are not binding and can be cancelled.

Microsoft released a video touting all the new features in the OS. Source: Microsoft

Microsoft is managing this well
In the past, the system of upgrading has been choppy. Windows 8 was not a free upgrade in most cases which almost certainly lessened initial demand. Because Win10 will be replacing a not-well-liked OS in Windows 8, first-day demand is likely to be very high and Microsoft seems to be on top of controlling the experience.

Windows 10 is a massive change from 8 and a pretty noticeable one from 7. It does return the familiar start screen and menu and it drops the tablet-like interface as the default setting, but it's still a big change. The OS has a new look for the Start menu, as well as a new browser, Edge, which replaces Internet Explorer. There are also new looks for familiar products like Microsoft Office.

The interface, however, which I have been testing as part of the company's Windows Preview program, is much more intuitive than 8. Anyone who has used an earlier version of the OS, other than Windows 8, should pick it up almost instantly learning new tricks and features as they go along.

This release is huge for Microsoft because the company may only get one chance to recover from the failure of its previous OS. Windows 10 should be able to do that and the company seems set for a carefully managed launch which minimizes user frustration.