UAC in windows vista is a way to protected windows operating system by preventing unauthorized changes to your system. This created lots of criticism and the feature which was built to make Vista secure became the most hated feature amongst users. In Windows 7, Microsoft has given options for the users to select their ‘comfort level’ in UAC notifications and also improved the user interface by providing more relevant and additional information.
Personally，in some respects, the “comfort level ” in UAC notifications is equal to Personal Firewall. When any applications want to modify or change the system configurations or settings such as changing the IE home page, modify the Registry, setting some services to “automatic”, and so on, even when the application will send a message to the Internet, the User Account Control will prompt to the users.
As a result, when the administrator was not used to the function, he had better take other security measures instead of turning off the UAC, for example, start the Personal Firewall which can do some of the core protection, although it couldn’t do all UAC could do. Of course, it was unnecessary to use the UAC control as promoting the Windows 7operating system, when the enterprise has deployed the personal Firewall. On the contrary, it will annoy users and arouse considerable complaints.
So, the system administrators just choose one of the two solutions, either UAC or Personal Firewall, according to the users’ and their own OS.