Vista allows a level of flexibility to what a user can or cannot do inside an OS. At the same time, Vista keeps security primarily in mind.Under Vista, there are two types of user accounts: the Administrator account and the standard user account. Standard User Accounts are equivalent to the similar standard user account in previous versions of Windows. They have limited administrative privileges and user rights. They cannot install or uninstall applications that install into system's root directory, change system settings, or perform other administrative tasks.However, standard users can perform these tasks if they are able to provide valid administrative credentials when prompted. What Vista does differently is how it treats the Administrator accounts. Vista limits the account privileges at the onset. With UAC enabled, members of the local Administrators group run with the same access token as standard users. The system grants the Administrator full rights only when the user grants the approval. This fundamental change is the cornerstone of User Account Control under Vista.UAC is enabled by default under Vista: on new installations, the first user account created is a local administrator account with UAC enabled.
All subsequent accounts are then created as standard users.UAC is a granular system and there are levels to the feature which determine how the system behaves. You might want to disable the feature altogether or instead, tweak the manner in which UAC behaves. To turnoff UAC altogether, you must be logged on as a local administrator. Open the Control Panel by clicking on Start > Control Panel. In the control panel's search box, type "UAC" and press enter. This will display a search result with the option to turn UAC off. Alternatively, you can click on "User Accounts and Family Safety" inside Control Panel and on "User Accounts" and finally on "Turn User Account Control on or off".Vista will prompt you for a confirmation. You will need to restart the system to accept the changes.Visit http://deepsource.blogspot.com for more information.