Taking ownership only changes the "owner" of the file or folder to be your user account. It does not change the permission level of the file.
After you have taking ownership of the item, you may still need to Allow
your user account Full Control
of the item before you will have full permission
to access it, to be able to modify, or delete it. See steps 11 to 22 (Option Three) in the tutorial below for how. Take Ownership of file - Vista Forums