An open-source OS that can run Windows software and drivers.
It is still very much Alpha software for now unfortunately (https://reactos.org/wiki/Installing_ReactOS).
As Windows is becoming more and more intrusive, ReactOS seems very interesting. But maybe the best thing to do is still to use Windows XP. I don't see what changed from Windows XP to Windows 10... They are basically the same, except that Windows 10 is worst.