If you want to use Group Policy to configure the 10 UAC related group polices so a Windows 7 client will be set to the third level on the slider bar:

“Default – Notify me only when programs try to make changes to my computer.  Gon’t notify me when I make changes to Windows settings.”

open your Group Policy Management tool and either create a new policy or edit an existing one (note I would NOT change the DEFAULT DOMAIN POLICY to protect against maiking a mistake).  Then expand to:

COMPUTER CONFIGURATION > POLICIES > WINDOWS SETTINGS > SECURITY SETTINGS > LOCAL POLICIES > SECURITY OPTIONS  and make the following changes:

Admin Approval Mode for the Built-in Administrator account = Disabled

Allow UIAccess applications to prompt for elevation without using the secure desktop = Disabled

Behavior of the elevation prompt for administrators in Admin Approval Mode = Prompt for consent for non-Windows binaries

Behavior of the elevation prompt for standard users = Prompt for credentials

Detect application installations and prompt for elevation = Enabled

Only elevate executables that are signed and validated = Disabled

Only elevate UIAccess applications that are installed in secure locations = Enabled

Run all administrators in Admin Approval Mode = Enabled

Switch to the secure desktop when prompting for elevation = Enabled

Virtualize file and registry write failures to per-user locations = Enabled