I'm running Linux Mint 15 Olivia on my netbook at the office. Initially I set it up to connect to the Internet using an Ethernet cable via our proxy-server. At home I connect using the WiFi connection.
Afterwards the PC losses the LAN connection when I return to the office. It no longer shows the wired connection in Network settings and can't connect at all. Switching the WiFi on/off on the PC doesn't help.