Router/internet/networking connection

I bought a Toshiba laptop and a router about 2 weeks ago, it worked fine after hooking everything up. Now all of a sudden I can't get internet connection and it is telling me that a network cable is unplugged. What do I need to do and how come it worked for 2 weeks. Noone has done anything different to the computer. I only go on to play Pogo.
My desktop computer is working just fine.