The dns problem for ubuntu

Actually I got this problem while using suse. How this happen I don't know; however, I know the solution I think.
The problem is opening another page which has a different URL entered. For instance, when you enter http://www.yahoo.com then the www.google com page opens. This makes the user crazy. If you live such things, it means you have a dns problem. But don't worry, there is a solution of every problem in Linux.

first you will press Alt+F2
you will see this box below

Enter the command:

gksudo gedit /etc/dhcp3/dhclient.conf

Then enter the password. You will edit the text on file dhclient.conf.
Find the line

#prepend domain-name-servers 192.168.1.1;

(this IP may differ)
and edit it like this

prepend domain-name-servers 195.175.39.39,195.175.39.40;

(don't forget to erase the shell at start of line)