Microsoft has nothing whatsoever to do with the DNS you use or the way your computer connects to the internet. Upgrading Windows Update Agent to v7.6.7600.320 did not cause your problem, whatever it is.
IN RE the Answer Desk: Once I've signed in to my Live ID (Microsoft account), www.answerdesk.com takes me to https://support.microsoft.com/answerdesk
Can you access this page? => http://answerdesk.microsoftstore.com
IN RE updates: Is KB2976627, KB2976897, KB2993651, KB2918614, KB2978668, KB2937610, and/or KB2943357 listed in Installed Updates (not Update History)?