There is some little software around to take ownership of files and folders in Windows 7. When I was installing Windows 7 Ultimate, I took ownership of all I could find. Then a few things no more worked and I had to reinstall... Luckily, I had almost only the basic installation done. I and others would certainly appreciate detailed advice about what you can without problems take ownership of, and where you should not do it. And also about the best software for the purpose.