User Account Control enables users to perform common tasks as non-administrators and as administrators without having to switch users, log off etc. User Account Control was developed to help prevent malicious programs silent installation and computer-wide infection.

By default, when you try to run an executable that has an administrative token (privilege), you’re prompted to consent to running the application as elevated. In order to run an application that has not been marked by the developer or identified by Vista as an administrative application, you must mark it to prompt for consent.

To assign an administrative token to an application, right-click an application, click Properties and then select the Compatability tab. Under Privilege Level check Run this program as administrator and click OK.

If the option is unavailable, it means that the application is blocked from always running elevated. It could happen in several scenarios: the application doesn’t require administrative token; the application is part of Vista; you’re not logged as local administrator.