Microsoft has expressed optimism on Wednesday that despite the worldwide slides on sales of personal computers, Windows will remain relevant in the tech world that has largely been transformed by mobile computing.

In order to adapt on the industry's changing landscape, and partly to catch up on the dominance established by Apple and Google over the past half-decade, Microsoft, according to CEO Steve Ballmer, is 'reinventing' Windows.

Speaking at a developers' conference held in Los Angeles, Ballmer revealed that once Windows 8 has been deployed, the new operating system will unleash new features that will mostly highlight its innovative 'cloud' functions.

"All the changes pivot around Windows 8 and its integrated cloud services," Ballmer was quoted as saying by the Wall Street Journal.

He added that this time around, Microsoft has re-engineered Windows 8 to perform seamlessly on notebooks, desktops, tablet computers and smartphones.

While acknowledging that the emergence of smartphones, tablets and cloud computing conspired in the steady declines of PC sales in the past quarters, Ballmer told The Associated Press that he remains confident with the new power to be exuded by Windows 8.

The new Microsoft OS, he added, will be the company's core strength in redesigning its business approach that will largely rely on 'cloud file-accessing', which was earlier picked up and popularised by Amazon and Google.

Ballmer is confident that once the final form of Windows 8 is released, Microsoft will have a déjà vu on its previous successes, which he said will be reflected by impressive sales figures of tablet computers and PCs powered by the operating system.

The same breakthrough applies on the mobile phone scene, where Microsoft hopes that the new version of Windows mobile OS will give afford it the fighting form it needs in competing with Google's Android and Apple's iOS.

On Monday, Microsoft issued the preview version of Windows 8 and since then, the company said that it has generated more than half-a-million downloads mostly from the developers' community.

On the back of its redesigned business model, Ballmer has projected that global retailers will push out some 350 million products, all of which revolves around the Windows architecture.

"There is nothing on the planet that will ship 350 million of anything other than Windows," the Microsoft chief told the WSJ.