User Account Control
The User Account Control, or UAC, is present in all versions of Windows beginning with Vista. A lot of people take umbrage at the UAC. Instead, it can be viewed as a useful security feature rather than an "annoyance". It was originally designed to allow all users to operate with Standard user privileges while doing away with the "log in/log out" routine every time an action required elevated privileges, which was the case with Windows XP and its use of Administrative and Limited user account types. By default, Windows will designate the first account created by the user an Administrator. Without the UAC, malware running under this account inherits the ability to elevate its own privileges and silently wreak havoc on your system. Since most home users are Administrators, and no anti-virus will block all threats, the UAC is an effective fail-safe. While it is true that a user who frequently installs/uninstalls programs or changes system settings will be plagued with prompts (especially the Windows Vista Home user), the UAC can be configured to behave differently in Vista Business, Enterprise and Ultimate editions and Windows 7 and 8. Furthermore, Microsoft has since relaxed the frequency of UAC prompts, for example, when system changes are initiated by the user as opposed to application software. Although it is possible to disable Secure Desktop mode (which is what makes the screen dim and forces a response), you should not do so as it is there to prevent spoofing of the UAC and disruption from third-party software.