Some people may be experiencing this problem, and Microsoft has a Fix It solution for it, as well as a manual fix if you want to go that route. If you are suffering from the problem, jump on over to Microsoft and get it fixed!
In the Windows 7 “System and Security” control panel category, the Action Center lets you change User Account Control (UAC) settings. In the User Account Control Settings dialog box, you move the slide bar control for notifications, and then you click the OK button. In this scenario, the dialog box does not close, and no change is made. When the mouse pointer is positioned on the OK button, and you press ENTER, the dialog box still does not close, and no change is made.