There is, and its getting popular http://zorin-os.com/ http://zorin-os.com/ there is another OS that is trying to build a windows compatible open source archite

There is, and its getting popular http://zorin-os.com/ http://zorin-os.com/ there is another OS that is trying to build a windows compatible open source architecture, but it hasn't got out of the alpha stage for the last 10 years, so I think the project is dead. The name of the OS is reactOS. I think they still have the website up.