I was unable to access some websites from my home machine like opera, comstat etc. While Google,yahoo, MSn does not have any issues. So i just searched for the solution. I found articles saying too many things to solve this issues, most of them failed.
Then I found an article at annoyances.org which did the trick. Now am able to access the sites with out any issues.
This need to add a registry value. So before you going to do this just follow some basic stuffs like.
1. Ping the site from command prompt
2. Tracert website from command prompt
If you were able to do the above step and got the sites connected the you can check with the annoyance article.
otherwise try to change your DNS address of your connection to open DNS, read it, also try to flush the DNS cache by running the following command from command prompt.
BEWARE WHEN YOU CHANGE THE REGISTRY VALUES, WHICH MAY HARM YOUR COMPUTER. DO IT AT YOUR OWN RISK