Just in case this hasn't been resolved yet, you can get to the laptop lid settings by going to Start Menu and finding "Control Panel." When there, choose Hardware and Sound > Power Options. When on the "Power Options" screen, the list of options on the left should contain "Choose what closing the lid does." Choose that option and you should see settings for "When I close the lid" when "On battery" and when "Plugged in." You could choose to set both to "Do nothing." I usually set the "Plugged in" option to "Do nothing" when connected to external monitors.
NOTE: There is a quick way to get here from the Settings app too. There should be a "Find a setting" search box on the left. Type "lid" in there and hit Enter. A suggestion should come up that says "Change what closing the lid does." If you select that suggestion, it will take you to the same Control Panel location I mentioned above.