Ubuntu 10.04 on a Dell Latitude 2100 netbook.
I just came across and solved this problem. Thought I would post it in case it might help someone else.
I just completed a clean install of 10.04 to replace the factory 9.04 install as support for 9.04 will be ending soon. I have discovered that when I lock the screen the wireless network connection disconnects. The computer disappears from my network and when I unlock the computer I see the message Newtork disconnected...
At least that was my first thought. Further testing showed that the disconnect actually occurs when I closed the screen on the netbook. This did NOT happen with Ubuntu 9.04
I suspected that this was something netboot/laptop specific. I looked at System; Admin; Power Management Preferences and low and behold I found "When laptop lid is closed:" The choice was set to "Suspend". I changed it to Blank Screen and the machine now stays on line even when the screen (or lid) is closed.
Ken
p.s. Why would I want a netbook on-line with the screen closed you ask? Seven watts is the answer. That is what the netbook draws with the screen dark - compared to 160 watts for my quad core desktop with the monitors off! If I have a large batch of data to download from usenet or elsewhere I queue it up on the netbook and let it do its low power thing
