Recently we replaced a user's XP computer with a Win 7 box. They use HyperTerminal to connect to a fuel pump that is at their facility. In the past when they were done with the pump they would disconnect the session and then press Alt+F4 to close the application. Now when they do this HyperTerminal closes but they get a blank white box on the screen that hides a portion of the desktop. You cannot see anything behind the box on the screen and it doesn't prevent you from working on the machine. The only way that I have found to make it go away is to log out and then back in again. Does anyone know the cause of this behavior or a way to resolve the problem?