Firefox 12 sidesteps UAC

User Account Control (UAC) in Windows 7 and Vista puts control over program installations and system changes in the hands of the users, requiring them to approve most such changes before installation software proceeds. The latest version of Firefox, v12, was released last Tuesday and it bypasses UAC so that updates can install without user interaction. This "silent updating" feature is similar to that of Google Chrome, which has bypassed the UAC prompt since it was first released four years ago. Note, however, that you do have to grant permission the first time. You can read more here:

http://www.computerworld.com/s/article/9226463/Firefox_skirts_Windows_security_feature_to_make_silent_updates_happen