1) Select Start->Control Panel.
2) If you have the standard Control Panel View you will see:
If you see a different screen (Classic view), go to Step 4.
3) Select Network and Internet Connections. Go to Step 5.
4) Select Network Connections.
5) Right-click on Wireless Network Connection and select Properties.
6) Scroll down to Internet Protocol and click on Properties.
7) Select Obtain IP Address Automatically.
You will now be able to select Obtain DNS server address automatically which is grayed out in the image below.
Then, click OK.