Abstract
Abstract Windows messages are the heart of Windows operating system, since they have been used to communicate with other programs and the system. When Windows receives user events, the system sends them as messages to the programs, in order to respond to the user requests. So, the system controls other programs using these messages. When a program user attempts to intercept system messages, it gives the ability to manipulate and modify or even discard messages bound to other programs within the operating system, which offers a chance to change the behavior of these programs, and consequently control them. This research presents software to intercept some types of Windows messages sent to other running programs to either modify or discard them. Additionally, software offers an ability to monitor the active program (that have been intercepted their messages by the program researcher) as well as all messages received from the operating system. The researcher used Visual Basic 6.0 to develop the software .
