File I can't take ownership of

Give Unlocker a try. If there is any open file handle it will let you close it so you can successfully delete the file.

If that doesn't work for some reason, try BootDeleter. It will delete the file for you upon reboot, before Windows has a chance to lock it on you.

Both utilities are freeware.

Sometimes it just won't let you change permissions because some process is using the file, or if you are trying to edit a folder's properties, then a process has a file that is within that dir or subdir open.

I had the problem described today, and I solved it by opening Process Explorer. Then, I went to the "Find" Menu, and selected the "Find Handle or DLL" option. In the dialog that comes up, I searched for the name of the folder I was having issues with. The search results told me which process had an open file within the folder. I killed the process, and then I had no problems with that folder's permissions.

Try Ultimate Windows Tweaker, which adds a "take ownership" element to the context menu.

Portable application, does not require an install.