How do I change the admin confirmation enter password box for guest

Hi, I would like to change the login prompt of administrators for the guest account to make them input the username and password, and not just the password automatically showing the user my account picture and username.

When I mean the prompt box I mean the one where they try to uninstall a program and the confirmation box appears asking for the password.

On my Windows 7 Home Premium 64bit computer, it only prompts for the password, and displays the administrator's picture and username automatically.

I was wondering if anyone knew how to change this so that the user would have to input the admin username and the admin password, and at the same time the picture wouldn't show, but would just be an outline/border of the picture.

I'm not running on a domain, as I am running on a workgroup.

I also can't go into Policy Editor since this is Home Premium, but was wondering if there was a way to do this via regedit?

For more info, I would like it to appear like the login screen here: Log On with User Name and Password

Thanks!

Thanks for the answer, but does anyone know of another way?

I can now use security policy editor and local policy editor. Anyone know of a way to make the guest enter the username and password when I'm running on a workgroup?