Ok it has been quite a while since I have been getting this error.
Earlier I had to use the ipconfig/flushdns command at least 30 times to get it to work.
Now I have figured out that it isn't a problem with the DNS server or my ISP, but a problem from my PC.
Here is what happens:
1.) Some webpages stop working. Loads after a few refreshes.
2.) If not, I have to use the ipconfig/flushdns as mentioned above.
3.) But if I change my DNS to either Google DNS or OpenDNS, the problem is gone.
4.) After 36-48 hours, the problem is back.
4a.) Change DNS to obtain automatic(setting DNS to ISP defaults)
And the whole thing repeasts itself.
Steps taken to troubleshoot issue.
1.) Uninstall, clean and completely remove the Network adapter drivers and software.
a.)Use default installed drivers
b.)Update using Windows Update
2.) Install latest drivers from the manufacturers website.
3.) Create new profile and test.
4.) Steps to fix a corrupt profile(http://windows.microsoft.com/en-US/Windows7/Fix-a-corrupted-user-profile)
I am fed up of chaging the DNS server every 48hrs. Isn't there anything permanent that I can do?