I had a lot of problems with security after I installed on my XP laptop. All of them have to do with accessing existing data and overwriting pre-existing files. Taking ownership etc all failed to allow me to access documents, make thumbnails of pictures work etc. I tried everything. Nothing worked in a straight forward manner. I got stuck. Then I looked at another laptop with Vista and noticed that the owners were different then on my new Windows 7 installation. I manually added Authenticated users, SYSTEM and Users. That solved most of my issues. AFAIC taking ownership of a directory should automatically fix this kind of issue. I now still have problems with some programs I installed because Windows 7 unexpectedly didn't actually format c before installing. This resulted in installing programs over existing program directories. This then resulted in similar security issues where some preferences settings aren't properly saved, presumably because the access rights are set incorrectly as described above. However, this is much more of a nightmare to resolve because I don't know which files are involved and I'm not sure of the proper settings or if I can just blanket replace rights over such directories as Program Files. Anyway, certainly a major imperfection in the installation process of Windows 7. Cheers, Marc