I'm trying to preview a screensaver inside a dialog window (much like the preview inside the Display Properties). I need to launch the Screensaver with the arguments "/p ####", where #### is the HWND of the window to launch in (I'm just wanting to launch it in an MFC text control). I can do the provew with my own screensaver that I wrote (I've got the CWnd class), but I want to actually launch an executable in there. I've tried ShellExecute and CreateProcess without luck, but I dont know how to translate the HWND to the command line. Any help?