Ubuntu 12.04 stopped connecting to the Internet
Three days ago, my Ubuntu 12.04 operating system stopped being able to connect to the Internet. Neither Firefox or Evolution Mail will connect. Firefox says the web-address is not available. Evolution Mail says the system is down. When I boot up, a message box comes up which says the Internet in disconnected. I have tried changing the connection to no proxy. The connection is currently system proxy. Any advice would be appreciated.