While working in Microsoft Excel 97, various warning dialog boxes are displayed to confirm that you aren't doing something destructive by accident. For example, overwriting an existing file, deleting worksheets, or closing a modified but unsaved workbook all display alert messages asking for a confirmation of your action. Setting the DisplayAlerts property of the Application object to False suppresses these warning dialogs (and many more) that occur during normal use while your procedure is executing.
Unlike in Microsoft Excel 5/95, in Microsoft Excel 97 the DisplayAlerts property is now persistent during cross-process automation. Therefore, when using cross-process automation you must explicitly set this property back to True before your procedure ends.