Microsoft's Windows 10 officially launched overnight, although many users won't get it straight away.
The new operating system - which is being gradually rolled out - replaces the last version which was criticised for the way the desktop looked.
Windows 10 will be free of charge for existing users of Windows 7 and 8 devices and sees the return of the Start button.
Joe Osborne from Tech Radar in the US, says Microsoft isn't charging most users as its strategy has changed.
"This is them following suit with competitors. (They) will use other revenue channels to make up for that - for example premium features within Skype."