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.
Key: .DEFAULT\Control Panel\Desktop