First of all you have to go to the networks and Open net work and sharing center-->
Now click on connections below the Access type :---> A network connection status pop up will open.
Now click on properties --->A pop up Window will open, there would be a check box coloumn of internet Protocol
Now double click on that a new pop up will come in which select general tab if not selected automatically
Then check the radio button of Obtain IP adress automatically .
Save it Bingooo you have done...just restart your network now.