User Account Control (UAC)

The biggest change in Windows 7 is the new User Account Control “slider” setting.
Windows chief Steven Sinofsky has admitted that Vista’s User Account Control had proved as popular as the village serial killer. The show-stopping interruptions are now completely under user control, with a sliding scale of UAC setting that ranges from turning the security “feature” off completely, to notifications every time a piece of software raises an eyebrow at your settings.