http://answers.us.samsung.com/answers/7463/product /NP-RF511/samsung-np-rf511-questions-answers/quest ions.htm?expandquestion=572025

Can I change how my RF511 behaves when I close the lid?
When on power I want the laptop to continue running. I want to be able to use and external keyboard, mouse, and monitor at my desk. I can do that; however, presently I have to leave the lid up or the system goes to sleep. The power setting for the action to take when the lid is shut are greyed out.
asked 2 years, 9 months ago
Njall
Monument, CO USA
on NP-RF511
Turn off Fast Start, that should allow you to change the settings. Either that or change the power setting from "samsung optimized" to something else and see if that lets you change it.
answered 2 years, 9 months ago
bfan