Installing Office 97 on Windows 7 can cause some unwanted results, such as no longer allowing end users to modify the settings of User Account Control in the operating system. Microsoft confirmed via KB978591 that
"In the Windows 7 "System and Security" control panel category, the Action Center lets you change UAC settings. In the UAC 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 doesn't close, and no change is made.
Note 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.
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