Gerade noch einmal nachgelesen (WM_QUERYENDSESSION):
Zitat:
Applications can display a user interface prompting the user for information at shutdown, however it is not recommended. After five seconds, the system displays information about the applications that are preventing shutdown and allows the user to terminate them. For example, Windows XP displays a dialog box, while Windows Vista displays a full screen with additional information about the applications blocking shutdown. If your application must block or postpone system shutdown, use the ShutdownBlockReasonCreate function.