I initially had this problem when I installed W7 RC x86. I didn't enter a username, password or product key. Later down the road, I found I needed certain administrator permissions to perform simple tasks, like deleting a file or moving a file. Long story short, I installed W7 RTM x64 and this time around, I entered a username, password and the product key I got from TechNet. So far, I have not had any issues at all regarding administrative permissions. Actually, I was copying over a file and a pop up appeared with 3 options (overwrite, rename and something else-i forget) and when I chose overwrite, it did ask me that I needed to be an administrator to perform this task, however, I was allowed to proceed and successfully overwrote the file because I am the administrator.