There's so little time between the OS hitting release to manufacturing (RTM) and the launch date that manufacturers won't have enough time to get systems in retail stores on July 29th but they should starting appearing shortly after that date.
The software also won’t be available initially to everyone -- instead the 5 million people who have been testing Windows 10 for Microsoft will get first crack at downloading it on July 29, the company said in a blog post earlier this month. New PC buyers who don’t choose to upgrade immediately in the store will also get pushed to the head of the queue to get the operating system when they wish, Mehdi said.Microsoft also revealed it will kick off a Windows 10 advertising campaign on July 20 in the US and July 29 globally.
A new global advertising campaign for Windows 10 will celebrate the newest generation and invites people to join a new era with us. July 20 in the U.S. and July 29 globally, the first wave of TV and digital ads will highlight how Windows 10 delivers a more human way to do - brought to life with features like Windows Hello and Microsoft Edge.