I have an application which calls another EXE using CreateProcess(..). This EXE is a standard window which can have multiple views. What I want is to be able to send a message to the EXE telling it to do something. I managed to get the HANDLE of the Window by searching for the title of the dialog. I issued a ::PostMessage(hWnd,WM_MYMESSAGE,0,0) to it, and have an ON_MESSAGE(WM_MESSAGE..) in the EXE source, but nothing happens. Could someone give precise answers to what could be wrong and how to solve it?