Sorry for not posting this in CODE tags, the menu isn't showing in my browser and I was unable to edit the previous post.

Code:
HWND notepad = FindWindow(NULL, "Untitled - Notepad");
 if(notepad)
    SendMessage(notepad,WM_SETTEXT,0,(LPARAM)"Message Recieved");
 else
    MessageBox(0,"Notepad isn't open.","Report",MB_OK);