W7 and W10

 https://www.itpro.co.uk/microsoft-windows/32066/what-to-do-if-youre-still-running-windows-7

https://www.youtube.com/watch?v=hPTKM4FyFSA

https://www.cnet.com/tech/services-and-software/still-running-windows-7-time-is-running-out-to-upgrade-to-windows-10-what-to-know/

https://www.zdnet.com/article/heres-how-you-can-still-get-a-free-windows-10-upgrade/

https://www.itpro.co.uk/operating-systems/28288/how-to-factory-reset-windows-10

https://www.av-test.org/en/?r=1