Microsoft’s next generation of its operating system, Windows 10, is due to be released next month.
The company said PCs and tablets running the software would go on sale on 29 July, at which point the OS would also be offered as a free download to existing users.
The roll-out of the product for smartphones, Xbox games consoles and other kit will follow later.
One expert said the release could prove critical to the Microsoft’s fortunes.
Windows 8 – the current iteration – has had a troubled life, with many deciding not to update to its touch-centric user interface.
The company has acknowledged the fact by returning some features dropped from the more popular Windows 7.