I rarely recommend system restore as a solution because most of the time system restore just mask the real problem and give a temporary solution.
But considering the fact that you tried all the above steps and none fixed the problem, try doing a system restore to a date when the internet was working fine in your computer.
This might cause the security software to block internet connection.
It is possible that your security software may have got corrupted or not working properly for variety of reasons.
I confirmed that my internet connection is working fine as I was able to go to google and look for search results.
The next step was to open these website with browsers such as IE, Firefox and Chrome.
You are always welcome to share your opinion on this. In some cases, this solution might be temporary as the error message might return after a week or month (This happened to me).Hope this article helped you in fixing DNS Server Not Responding Error.Feel free to add your comments and questions if you need any help on the topic. A Tech Enthusiast|Blogger|Tech Trainer with 10 yrs experience in the field of IT.The trick now, is to remove the global DNS and go back to select “obtain DNS server address automatically”. Switching between alternate DNS server address and automatic DNS server should fix the problem.System restore feature enable you to restore your computer to a previous date and time when the computer was working fine.