The entire concept of UAC and programs not running by default was introduced in Vista. It was such a big change that it pretty much ruined the reputation of the OS, single-handedly. I remember that one of the major complaints about Vista was the number and intrusiveness of UAC prompts, which occurred because programs were doing things like keeping settings in C:\Program Files, rather than the user&#x27;s application data folder.<p>Windows 7 has the same permissions model as Vista, but has a much better reputation, because by the time 7 was released, applications had been updated to not require as much in the way of permissions. From the users perspective, this meant that 7 &quot;worked properly&quot;, even though little had changed in terms of the security model between Vista and 7.