403 error on BSNL -- changing your DNS

I have had some severe problems recently in connecting to the internet, running into a “403 Error — Forbidden” message for several popular websites. The reason is probably a virus which redirects internet requests by my computer to some very strange sites which look like a fancy search engine interface but do not seem to do anything. It was not clear where this virus was, on my computer or on the DNS server of BSNL, which is my ISP. The last time the problem occurred, a full scan by malwarebytes (free!) did not find anything, so I reset my DNS to the google public DNS.

This I did (under Windows XP) from the Network Connections tab under Control Panel. Select your connection, open the “Change settings of the connection” tab from the left, select TCP/IP -> properties, then under DNS open “Advanced” and enter the DNS addresses 8.8.4.4 and 8.8.8.8. Then move them up to the top of the DNS list by clicking on the arrow. You may want to restart your modem after this.

It is  usually a good idea to write down (using pen and paper!)  all the settings before you change them, so that if your computer crashes and settings are lost, you can at least go back to the old settings before calling for further help.