- Microsoft offers free trial of Windows 8 and revs up to battle Apple and Google
- Touchscreen operating system available free to test
- Will work on tablets as well as PCs
- Tablet users will enjoy Microsoft Office for free
- 'Make-or-break' opportunity for ageing tech company
- Demo is downloaded by users in 70 countries
- 'Your desktop is dead' - Wired magazine
It is a make-or-break moment for Microsoft that will either propel it back to the forefront of personal computing or see it lag further behind its arch rival Apple.
The world's largest software company gave reviewers and the public their first taste of its revolutionary new operating system Windows 8 yesterday.
And, no doubt to chairman Bill Gates' enormous relief, the most radical reinvention of Windows since its 1985 launch has been met with glowing reviews.
One impressed tech writer gushed: 'This is the future of computing.'
Windows 8 will run on tablets as well as desktops and laptops - and is a sea-change for Windows that is seen as a make-or-break opportunity for Microsoft.
Tablets and cloud computing have made Mr Gates' vision of ‘a computer on every desk and in every home’ seem quaint - Windows 8 aims to adapt the iconic operating system for life in the mobile world of tablets.
Windows 8 will come in two variations - one that works on desktops and laptops, and a new version for the ARM microprocessors in tablets, smartphones and other portable devices.
There is no set release date, but it's widely expected to be available in autumn - offering Microsoft Office free on tablets, which could be a 'killer app' that puts Windows 8 machines ahead of Apple devices.
In both versions, Windows 8 features a completely new interface, borrowed from what Microsoft calls the ‘Metro’ style of the current Windows Phone software.
WINDOWS 8: ALL CHANGE FOR WORLD'S BIGGEST OS
Touchscreen compatible - the new operating system will work with tablets and portable devices. There will also be a version for PCs.
Fewer windows - instead of 'stacks' of windows, as in previous versions, the OS is built around clean 'tiles' that deliver information to the home screen.
Free versions of Word, Excel and Powerpoint - Windows 8 will offer Office free to tablet users.
Business-friendly tablets - Windows 8 will work smoothly with Microsoft Exchange email systems, so could be highly popular with business.
Apps shared with phones - apps in Windows 8 will be built to work smoothly with phones (such as Nokia's) running Microsoft's Windows Phone OS.
Easier passwords - users will be able to unlock PCs with a PIN, or by circling details in a picture.
No Start button - instead, users will access a menu from a 'hot corner' in the bottom left of the screen.