They offer the Thing firstly for free..then dump it on wether you want it or not
If ,like me, you are still using Windows 7 ,you will receive a message from Microsoft to the effect that they will update your system automatically on 31/May , to Windows 10.
If you don`t want "10" ,Do not click on the red "X" at the top right hand corner,instead go to to the "Do not install " option in the text.