Has Microsoft fumbled its tablet vision?
Microsoft's famously exuberant boss Steve Ballmer was the first to show off Hewlett Packard's Slate tablet PC in January 2010.
Before Apple's iPad had even been announced, this device was real. It worked, and it ran Windows 7.
Ballmer held up the Slate on stage at the Consumer Electronics Show in Las Vegas, proclaiming it to be "perfect for reading, surfing the web, and taking entertainment on the go."
Ten months later and the Slate is yet to materialise.
Meanwhile, various touchscreen tablets running Google's Android operating system have been launched and Apple has sold more than four million iPads during the last quarter alone.
Estimates suggest it is on course to have sold around 12 million by the end of the year.
Watching rivals gobble up a potential market is no doubt galling for HP.
However, it is Microsoft that is seen as having fumbled the ball, according to industry watchers.
"Nothing will save Windows in the consumer tablet market, they don't have an operating system suitable for it," said Devin Coldeway from blog Crunchgear.
"[Apple's] iOS, [Google's] Android 3, and [Palm's] webOS will completely dominate it."
Steve Ballmer has criticised the proprietary software used by his rivals, including Apple, calling them compromise devices.
But several hardware manufacturers have begun sidelining their Windows 7 plans in favour of other tablet operating systems.
Some cite Microsoft's touchscreen interface, saying it is far from optimised, and feels fiddly when compared to other systems such as Android and the iPad.
But the bulk of the criticism relates to Windows 7's gluttonous power requirements.
"Based on the current technology, it needs more power to drive Windows 7, but with more power there is more power consumption, and in the tablet market more power consumption is not allowed," said Andy Tung, vice-president of sales for electronics firm MSI.
MSI has delayed the launch of its Windows 7 WindPad as it awaits Intel's next generation Oak Trail mobile processors.
In the meantime, it plans to release a version running Android.
Even with suitable hardware, MSI believes interest in a Windows tablet will be limited to the enterprise sector - businesses and education customers.
Such a prediction flies in the face of Steve Ballmer's vision of users browsing the web and watching movies on Windows 7 tablets.
The world's largest PC manufacturer, Hewlett Packard, also seems to be losing faith in Microsoft.
Its 'Slate' device had become the poster boy of Windows 7 tablets after Steve Ballmer used it to demonstrate the product at the 2010 Consumer Electronics Show.
HP has since announced plans to launch the Slate running Palm's WebOS, after it acquired the phonemaker earlier this year.
"WebOS is the core roadmark operating system that we have for tablet… we do have a Windows 7 tablet that will be very focussed on enterprise," said Steven McArthur, HP's senior vice-president of consumer applications and services.
Once again, it is Windows 7's sheer heft that is being blamed.
"If you look at the operating systems such as WebOS that are built specifically for the mobility experience, you start to see much lower demand for memory, much lower demand for processing power, and much longer battery life," added Mr McArthur.
One possible solution to Microsoft's tablet woes is Windows Embedded Compact (CE), a stripped down version of the operating system that can be customised to run on devices with lower hardware specifications.
At least one company - Asus - has demonstrated a working prototype.
However, Microsoft has so far shown little enthusiasm for CE as a tablet platform, according to Makran Daou from tech news website Mobiletechworld.
"It currently doesn't seem to push the use of CE hard enough and wants to focus on trying to adapt Windows 7 to Slate devices."
He added: "Microsoft has to really focus on a real tablet strategy from top to bottom.
"My guess is that we won't see anything major until Windows 8 comes out probably at the end of 2012."
Some observers point out that Microsoft already has a potential answer to the tablet problem - Windows Phone 7.
The interface is regarded as being more touch-friendly than Windows 7, and could be scaled up from phones to larger devices.
The company also plans to build a 'marketplace' of downloadable software for Windows Phone, similar to those available on iPad and Android.
"Applications are a big part of the iPad's success and they will play a key role in Android based devices," said Gartner mobile device analyst Carolina Milanese.
"One has to wonder if Microsoft would be better off using Windows Phone 7 and leveraging the investment it is making in the marketplace," she added.
Windows Phone 7 - launched in Europe and the Asia-Pacific region on 21 October, and the US on 8 November - has received a positive reaction from the technology press.
But if Microsoft has any intention of bringing the Windows Phone 7 operating system to tablets, it is yet to say so publicly.
All the while, its rivals clock up sales and continue to consolidate their positions in technology's most talked-about sector.
Microsoft declined to be interviewed for this article.