connectTwoprogram.zip ProgramA.au3 #Include <WinAPI.au3> #Include <SendMessage.au3> #include <ButtonConstants.au3> #include <GUIConstantsEx.au3> #include <WindowsConstants.au3> Global $ConnectOK = 99999 , $iGuiHwnd = 0 , $ConnectHWnd , $ConnectMsg $GuiHwnd = GUICreate("ProgramA", 199, 147, 88, 177) $Button1 = GUICtrlCreateButton("GetConnectHWnd", 16, 16, 169, 33, $WS_GROUP) $Button2 = GUICtrlCreateButton("SendMessage", 13, 69, 169, 33, $WS_GROUP) $ConnectMsg