Internet Problem

Hello Friends,

I am not able to open the anti virus webpages and also microsoft webpages by putting their domain name but if i am entering their ip address in the internet explorer bar , then the websites are opening. I am using Mcafee Internet Security 2009. Few days back it said some changes in the registry have been done and it was not able to stop and after that I am not being able to update the mcafee anti virus and also not being to open the webpage by their domain name. I had used mcafee registry cleaner and the first time it showed around 500-600 changes in the registry had been done and it removed but there is one change happening in the registry everytime i switch on the computer and then it gets cleaned by the registry cleaner. I have searched in the internet about the problem but I am not able find its proper solution. Please help me with it.