Microsoft said:An application that is running in the RealTime priority class (a base priority of 16) can potentially take so much of the available CPU resources that no resources will be available for other processes or threads. This includes a possible "starving" of both the mouse and keyboard. This implies that the mouse may become unavailable to click another application to execute an action. It also implies that the keyboard may not respond if you try to press CTRL+ESC to get the Task List and Cancel the application.