MICROSOFT'S latest move in the marketing of its critically important new operating system, Windows 8, comes straight from the manual of used-car salesmanship: a tactic that industry calls ''puppy dogging'', in which the prospective buyer is allowed to take the vehicle home overnight, on the likely assumption they will form an attachment to it.
In essence, that's what the so-called ''consumer preview'' of Windows 8, which notched up more than 1 million downloads on the first day of its release last week, is designed to do: convince users it will be worth their while to adopt - for an as-yet-unknown price - what Microsoft Windows division president Steven Sinofsky describes as ''generational change'' in computing.
The set-up site is at bit.ly/AC9D52. The 64-bit (3.3 gigabytes) and 32-bit (2.5GB) versions can be downloaded as ISO images from bit.ly/zF2NTS. The site also offers a set-up package with tools to convert the images into DVDs or USB bootable flash drives so they can be installed on separate hard-disk partitions, dedicated PCs or virtual machines.
The ''generational change'' has been forced on Microsoft by the migration away from its desktop operating systems to smartphone and tablet environments dominated by Apple's iOS and Google's Android.
Microsoft has spent three years coming up with its version of the physics world's Grand Unified Theory - which it maintains will seamlessly deliver the ubiquity and convenience of the mobile environment and cloud-based services and the power and flexibility of the desktop or notebook within a common, touchscreen-capable user interface it calls Metro. It's also been designed to run on smart TVs.
At the preview launch - significantly, at the Mobile World Congress in Barcelona - Sinofsky described Windows 8 as Microsoft's most radical redesign since Windows 95.
The new operating system stores users' preferences in the cloud, delivering personalised desktops on any Windows 8 device when they sign on using a Microsoft ID.
On a touchscreen device, users can unlock features using gestures, accessing a series of screens with collections of ''live tiles'' or app icons, animated by content, including the latest posts to Twitter or Facebook.
Sinofsky claims the ability of Windows 8 to adjust features according to the capabilities of a device is a significant advance.
''We too often have to choose between consumption and productivity, more battery life or functionality, a tablet or a laptop, a touch interface or keyboard and mouse,'' he says. ''You want to have these capabilities no matter where you are or where you are working. The operating system should just scale with you.''
That statement is somewhat moot. Windows 8 is, in many ways, a distinct improvement on its predecessor. It boots faster and is more responsive.
But the Metro overlay that replaces the old Start menu, removing the familiar Start ''orb'', has infuriated many experienced Windows users, who claim its simplicity interferes with their work flow. While it can be quite powerful in the world of smaller touch devices, they say it is an impediment to keyboard-and-mouse multitasking.
Early desktop users of the consumer preview reported difficulties shifting from the Metro view to the desktop and found it impossible to close Metro apps.
One site that might provide assistance is windows8beta.com - but Microsoft will face increasing pressure to allow desktop users to retain more of its familiar elements, or easily switch between environments.
And while tablet users are happier about Windows 8, success in that area will depend largely on third-party developers.
Microsoft has also launched the Windows Store for Windows 8, providing apps for the new software environment.
The beta version of Windows 8 can already be populated by dozens of applications, including redesigned versions of the WordPress.com blogging software and Amazon's Kindle e-book reader.
Some observers even claim that Windows 8, running on the cheap ($US199, $185) Kindle Fire tablet - while requiring additional RAM and internal storage to run the new OS - is a potential iPad ''killer''.
But matching the attractions and volume of offerings on Apple's iTunes App Store and the Android Market represents quite a challenge for Microsoft, although it is trying to stimulate development by running competitions for developers.