I have the same problem on a Dell Latitude E6400 laptop. Neither the screensaver nor the display power management work on the external LCD monitor. I'm not sure about the laptop's LCD screen itself (a member of our staff uses the laptop, I do not). I will check the laptop screen screensaver/LCD power management when I have time... perhaps it's just a bug with external monitors... perhaps Win7 thinks its in Projector mode or something, so it doesnt turn the screen off???