Getting Started (SQL Server 2008)

I spent days trying everything suggested for getting permission access correct on a fresh install and finally I found the trick, basically even if you are an administrator your not. You have to enable the hidden administrator, log in as the hidden administrator, set up users and permissions, then you can disable the hidden admin and use your credentials to move forward.

here it is - good luck and hope it helps:

http://www.howtogeek.com/howto/windows-vista/enable-the-hidden-administrator-account-on-windows-vista/