If you don’t want to upgrade to Windows 10 and that icon in the corner is bothered you to telling to upgrade or you are worried that someone might click it there is something you can do!
Unfortunately Microsoft want you to upgrade whether you want to or not and don’t make it easy to disable that icon. There is a free piece of software called GWX Control Panel that allows you to disable the annoying popup icon.
GWX Control Panel http://ultimateoutsider.com/downloads/
Please be advised that while Agile Computing has used and tested this software, Agile Computing does not produce this software and cannot be held responsibility for issues with installing it.