No charge for Windows 10 upgrade

Seattle

NEXT week, when Microsoft releases Windows 10, the latest version of the company's operating system, the software will offer a mix of the familiar and new to the people who run earlier versions of it on more than 1.5 billion computers and other devices.

There will be a virtual assistant in the software that keeps track of users' schedules, and Microsoft will regularly trickle out updates with new features to its users over the Internet. And the Start menu, a fixture of Windows for decades, will make a formal reappearance.

But one of the biggest ch…