NT registry tip 77 gives the hack to activate the screen saver when no one is logged on. There is a security risk as I document in Admin Tip #262 to replace login.scr which can be used to hack into an NT / Windows 2000 / XP systems. The exposure requires physical access. The real control involves restricting physical access. But if you want to prevent the logon screensaver from launching, use the following NT / W2K /XP registry hack.