This is a problem i been dealing with quite some time now, thanks for all help! I have a MB Air with a USB ethernet adapter, and i been trying to get my work's network to get along with my Air. When i connected the ethernet with my Air this morning, everything worked well, but 3-4 h later, when i restarted the computer, the ethernet didn't worked any longer. So i tested the connection with Boot Camp (XP), and the same problem there, works until i restart the computer. What is the problem? OS X? XP? MBA? The network? The USB adapter?