Later this week Microsoft will provide more details of Windows 10, most likely focusing on how the new operating system will look and feel on smartphones and tablets.
According to Mary Jo Foley, Microsoft is likely to unveil a version of Windows 10 that's expected to work on Windows Phones and smaller Windows tablets running ARM and perhaps Intel processors.
Microsoft will be hoping that by making it easier for developers to build for tablets and smartphones it can take some of its dominance of the desktop world and port that to the mobile world.
That may help a bit, but will not in itself create the breakthrough that Microsoft wants: when it comes to mobile, Microsoft's Windows Phone is still a distant third in a two-horse race.
Microsoft is generally considered to have lurched too far towards mobile with Windows 8 in an attempt to head off the threat from tablets.
This had the effect of scaring off more conservative business customers who worried about how to retrain staff for the operating system's tiled user interface, but also failed to win over tablet fans either because of unremarkable and expensive hardware. The company has made some moves to make its tablets more attractive in the form of cheaper licensing for tablet makers, but it's still an uphill battle.
As such, with Windows 10, Microsoft has to demonstrate to consumers why its proposed ecosystem works for them: why a consumer with a PC, tablet and smartphone all running Windows is better off than, say, someone with a Windows PC, an Android tablet and an iPhone.
But that's not the only battle that Windows 10 needs to win.
The desktop OS to beat: Windows 7
In the desktop world, Microsoft's biggest competitor is always itself. Or rather, in this case, Microsoft circa 2009, which is when Windows 7 was launched. According to figures from Netmarketshare, Windows 7 still accounts for 56 percent of the desktop market. Windows XP (launched back in 2001) is on 18 percent, while Windows 8 and 8.1 combined come in at about 15 percent, which shows just how well Windows 8 has performed.
As these figures show, in business the challenge for Windows 10 is not to be better than Windows 8 -- it's to be better than Windows 7. The days when businesses would shrug and then just get on with upgrading to the next version of Windows are long gone.
Microsoft has to make a compelling case for why its customers should spend the money. And while some of them may be interested in deploying apps across PCs, tablets and smartphones, the majority are still focused on the spreadsheets, documents and presentations that form the basis of office productivity.
Of course, Microsoft is hardly a one-product company. But Windows is still vital, and getting it right this time around is essential. Still, there are a few points in Microsoft's favour already.
First, what we've seen of Windows 10 so far has been well received; second, enterprises tend to skip one version of Windows and seize on the next, which could result in a big jump onto Windows 10. And on top of that, since Windows 8 launched in 2012 the device market has changed again: while the explosive growth of tablets was once expected to annihilate the traditional PC and notebook markets, it seems that the PC is enjoying something of a renaissance which Windows 10 could be well timed to capitalise upon.
Further reading on Windows 10