If when you try to change the User Account settings in Windows 7, after you have made the change, the dialog box does not close, and no change is made, then you may want to read this article.
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. If you click Cancel, the dialog box closes and no change is made, as expected.
This issue occurs when Microsoft Office 97 is installed on Windows 7. The installation of Office 97 makes a change to the registry that causes this issue.
To set this right, Microsoft has released a Fix It solution.
To download and apply this Fix It, head over to KB978591!