I use a 2010 MacBook Pro running the latest version of Mountain Lion. When I am home, I connect my monitor to my laptop and close the laptop. When my laptop is closed, it doesn't get any WiFi reception so I use an ethernet cord. Initially, the ethernet works fine. Randomly, my laptop will stop getting any internet. If I am patient enough, after some time (a few minutes, sometimes even longer) the internet will come back. I will be connected just fine until I lose connection again, etc. Restarting the computer doesn't help. Restarting the router doesn't help. I tested the laptop with the same ethernet but without attaching my monitor. The internet works just fine. I also tested the laptop plugged into the monitor with the same ethernet but kept the laptop open "dual monitor" style and it worked fine. It must have something to do with closing the laptop. Does anyone have any suggestions? Thank you for your help. For the record, I am using a TRENDnet PowerLine Adapter.