Web pages could not be opened though PC showing Ethernet connectivity.

Which browser are you using.

This is most probably due to browser having issue, as unable to open the website.
Have you try to update your browser &or use another browsers, such as, IE, Chrome, etc.

Updates and other related but not require any browser will work, as direct link, such as Windows updates.

In addition, do a quick scan, by using another Antivirus, such as SuperAntiSpyware.com free edition.
It is best to try another Internet Security, as 2nd opinion.
I had 1 active Internet Security but not detecting malware, spyware; hence i had to use the superantispyware, which detected a lot of malware, etc.

Thanks for your response, sorry but I forgot to mention that no browser issues there as I have tried it in Chrome, IE and Firefox.
Pretty irritating issue.

That is strange.
I am using Chrome for a very long time, i think when there is IE4.

For your info.

Chrome version 52.0.2743.82 m (64-bit)

Set the to 208.67.222.222 & 208.67.220.220 see if that fixes it also check no proxy is set in the browser if it still doesn't work from a Cmd prompt type tracert site name is tracert ms.com post results