Here are some REG files below that I created that will set this policy setting in all editions of Windows 7. You will need to log off and log on, or restart the computer after merging the REG file to apply.
However, this policy setting doesn't stop a UAC prompt while installing say CCleaner though.
User Account Control: Detect application installations and prompt for elevation.
This policy setting controls the behavior of application installation detection for the computer.
The options are:
• Enabled: (Default for home) When an application installation package is detected that requires elevation of privilege, the user is prompted to enter an administrative user name and password. If the user enters valid credentials, the operation continues with the applicable privilege.
• Disabled: (Default for enterprise) Application installation packages are not detected and prompted for elevation. Enterprises that are running standard user desktops and use delegated installation technologies such as Group Policy Software Installation or Systems Management Server (SMS) should disable this policy setting. In this case, installer detection is unnecessary.