I believe this is a duplicate of bug #990908 ('Won't honor "Do Nothing" when Lid is Closed'). As described in that bug, the computer suspends when the lid is closed even though you've selected "Do Nothing" in the power preferences.
-- You received this bug notification because you are a member of Desktop Packages, which is subscribed to gnome-power-manager in Ubuntu. https://bugs.launchpad.net/bugs/995840 Title: When laptop lid is closed screen locks even if it should not Status in “gnome-power-manager” package in Ubuntu: Confirmed Bug description: In power options the settings for When lid is closed are DO NOTHING both for on battery and on line power. But if I close the lid the computer locks. ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: powerman (not installed) ProcVersionSignature: Ubuntu 3.2.0-24.37-generic 3.2.14 Uname: Linux 3.2.0-24-generic x86_64 ApportVersion: 2.0.1-0ubuntu7 Architecture: amd64 Date: Mon May 7 11:39:04 2012 InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425) SourcePackage: powerman UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/gnome-power-manager/+bug/995840/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp