I had a file that I just could not delete in Windows 7. The file was created on a spare drive when I still had Windows XP installed. After numerous failed attempts I found a blog entry that includes a registry entry that will allow you to take ownership of the file by righ-clicking. Yes, registry entries are scary, but it did allow me to delete the file. You can check out the blog entry here:
Thanks to Blogsdna for the article!