Are you asking whether you can set the screensaver to scan the startup and memory, instead of your drives?
Well, I think in Professional version, you could edit the ScreenSaver task and modify its area to test. You could put Startup there (even All Users Startup)... as for the memory, I'm not completely sure. You can set the "real memory" scan there, but the Splash screen tests just the modules loaded in memory in fact.
Or maybe you're asking about something else?