cable internet not working

Plugging the ethernet cable, how to operate internet w / o restarting the computer?
I'm in college and I sometimes have to disconnect my cable and when I plug ethernet back to restart the computer, Internet will not work. As in I will have a local access network .. but no Internet access. Is there some way to type a command somewhere in the system command, or perhaps somewhere else that allows me to reconnect without rebooting the computer?
Right-click the connection icon (looks like a small PC), bottom right and select Repair.
How to connect your ps3/Xbox 360 to the internet using an Ethernet cable (READ DESCRIPTION)
