I want to change DNS address but when in "Network connection properties" I select the "Internet Protocol Version 4 (TCP/IPv4) line the Properties button is not active and I can not click it to open and change the DNS address. Also I see now that Properties button is inactive for all the other lines too.. I can't find the reason of that.. Did I restrict something by mistake? or is it another problem.. I'm on Windows 7 Home Professional.. Please Help me to fix this situation..