Unable to use Windows Update

I am trying to use windows update, but it says I need administrator privileges. My user account is an administrator account, and even if I log on as Administrator with the default account It won't let me update. HELP!

Supergroomer

This excellent tutorial may be able to help
http://www.sevenforums.com/tutorials/112765-windows-update-enable-disable-who-can-install-updates-setting.html

If the problem remains.

Type windows update in search, right click when it pops up>then run as administrator.
If that does not work, bring it up in search, right click and then properties. In properties go to security. In security make sure that you have all the correct permissions.
http://www.sevenforums.com/tutorials/24232-sharing-permissions.html
Permissions are the same for Vista and Seven.