Microsoft's much-heralded Windows 7 went on sale around the world Thursday as the US software giant seeks to reboot after the disappointment of its previous generation operating system Vista.

Windows 7 made its global debut to generally good reviews with most technology analysts and users who tested a demo version praising it as a significant improvement on the much-maligned Vista.

- We think our customers will enjoy the new capabilities, the speed, the performance - Microsoft chief executive Steve Ballmer said at a Windows 7 launch event in New York. - There's more you can do with this system.

- The range and diversity of the application software is unsurpassed.-

Now we see if real people love Windows

By the time the day was a minute old, Microsoft workers were handing out Windows 7 software as gifts at a party the US technology giant held at a San Francisco night club to coincide with a Web 2.0 Summit here.

- Now we see if real people love Windows - said Brian Hall, general manager of Microsoft's Windows Live business group.

Feedback from the millions of test users has Microsoft confident they have hit the mark with the new-generation operating system, which reportedly logged more pre-orders in Britain than did the final Harry Potter book.

- This is the most customer excitement we've had in a long time for a Windows release - Hall said.

Microsoft is also celebrating the availability of Windows 7 with parties and by opening its first retail shop in the US city of Scottsdale, Arizona.

The shop features netbooks, laptops, desktop computers, Zune players, Xbox 360 videogame consoles, and mobile phones running on Microsoft software.

A second Microsoft store will open in northern California next week.

Microsoft on Thursday also began selling Windows-equipped PCs from companies such as Sony, Dell, and Lenovo in its online store.

- Our customers have told us they want choice, better value and great service when shopping for technology, and that is what we will deliver through our Microsoft stores - said Microsoft corporate vice president of retail David Porter.

Microsoft hired Porter, a retail industry veteran, in February to open retail stores that challenge the successful chain of Apple Stores operated by the maker of iPhones, iPods, and Macintosh computers.

Windows 7 launch is a big deal for Microsoft

The launch of Windows 7 is expected to open the flood gates for low-priced, feature-rich personal computers based on the operating system.

- We have great PCs coming out for Windows 7 - Hall said.

Analyst Rob Enderle of Silicon Valley's Enderle Group said the Windows 7 launch is a - big deal for Microsoft.... Windows Vista was a train wreck - he said.

While computer users may not give much thought to the operating systems that serve as the brains of their machines, they are at the heart of Microsoft's global software empire and run more than 90 percent of the world's computers.

Microsoft apparently learned a lesson from Vista and worked closely with computer makers, users and software developers while crafting Windows 7.

More than eight million people have dabbled with Windows 7 since Microsoft began a beta test phase in January, according to Parri Munsell, director of consumer product management for the Windows client group.

Among the new features in Windows 7 is a redesigned taskbar for launching programs and switching windows, enhanced ability to share files with other PCs, improved photo and video editing software and the ability to stream digital music or video to other devices.

Windows 7 also features Microsoft's latest Web browser, Internet Explorer 8.