Maury was one of several readers who complained about the Windows 10 upgrade starting without user permission.
I have been hearing a lot about this recently. Another reader got to the point where he was scared to boot, assuming that the installation would happen right away.
If the Get Windows 10 icon has become either an annoyance or a serious problem, you can easily remove it with Ultimate Outsider’s free and portable GWX Control Panel. You download this program as a single EXE file.
Once it’s up, you might want to look at some of the information on the top part of the program. For instance, I discovered that I had apparently “enabled” both the Get Windows 10 app and the upgrades. I had not.
Click two of the buttons near the bottom, Disable ‘Get Windows 10’ App (permanently remove icon) and Disable Operating System Upgrades in Windows Update.
Launch and run the wizard. The choices are pretty obvious. In my case, I got a disheartening error that one update problem could not be fixed.
Source: http://www.pcworld.com/article/2998967/windows/how-to-block-the-windows-10-upgrade.html