If you do not want windows 10:
1. open task manager once pc gets to desktop ( end task ) GWX
2. open window updates - go to "optional updates" remove checkmark for windows 10
Microsoft has by default started forcing windows 10 on everyone who are using:
vista - windows 8.1
P.S. - these are ways to stop windows 10 from installing automatically or simply stopping the process to get rid of icon in lower task bar temporarily.
July 29, 2016 is the last day windows 10 will be available for free.