See this, i think problem is with your network card. Do check wheather the network card is working proprelly or not. But before that you have to make sure that you have installed the right drivers for network card.
For that just right click on My Computer -> Click on manage -> Device Manager -> Network Adaptors -> In this check wheather you are getting right netwrok card or not.
If not then for sure there is a problem with your drviers. Install drivers again n this will solve your problem.
And if you not get your problem solved then please reinstall all drivers of your machine. May be it is coz of some file missing.
And still you are getting same problem, then friend you have to change your network card. Change it and check wheather you are getting same prob or not.