Most user activities, such as surfing the Web, sending email, and using productivity applications, do not require administrative privileges. Yet most people log on to their home PC with an account that has full administrator privileges. This puts the PC at greater risk from viruses, spyware, and other threats.
User Account Control (UAC) in Windows Vista makes it easier to use your PC with standard user privileges. You can create a separate user account for each member of the family and control which websites, programs, and games each person can use and install.
UAC also helps families with children protect their PCs from malware such as viruses, worms, and spyware that might be hidden in programs that appeal to children. UAC makes it practical to give children their own standard user account, so that if a child tries to install a new piece of software, the system will prompt for an administrator account password to approve the action.
Even when you use an administrator account, UAC provides additional protection. By default, most programs run with the permissions of a standard user, which limits the potential damage they can do.
If you need to start a program that requires administrator privileges, the system will prompt you for an administrator password.