[CentOS] no access to certain WEB sites using CentOS 6.5

HW:
Lenovo T520 laptop with MS WIN 7
        OR
dedicated PC (DELL GX 280)

SW:
CentOS 6.5 (64-bit)  installed using VMware Player on MS WIN 7 host
CASE A)  -- BRIDGED networking selected
CASE B)  -- NAT networking
              OR
CentOS 6.5 i(32-bit) nstalled on real HW (DELL OptiPlex GX 280)

___issue____  at hand:

The default Firefox ESR browser (17.0.10) does not find many web pages.
regardless of the system (virtual - bridged or NAT  OR real HW)

For example:
https://www.google.com/  works
When I enter into search field string 'opera browser'
https://www.google.com/search?q=opera+browser&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:unofficial&client=firefox-a

I do get a lot of results back. So far so good.

Then I click on the first searched  link http://www.opera.com/
I get back

Server not found
          Firefox can't find the server at www.opera.com

Then I open gnome-terminal and  type
ping www.opera.com

I get back  __nothing__

[igor at localhost ~]$ ping www.opera.com
PING www.route53.opera.com (54.244.236.138) 56(84) bytes of data.

but

when I type

ping opera.com

I get back

[igor at localhost ~]$ ping opera.com
PING opera.com (185.26.182.79) 56(84) bytes of data.
64 bytes from front-ams.opera.com (185.26.182.79): icmp_seq=1 ttl=41 time=174 ms
64 bytes from front-ams.opera.com (185.26.182.79): icmp_seq=2 ttl=41 time=122 ms

========================
another example
========================
http://www.delo.si/      works
http://www.dnevnik.si  does __not__ work

http://www.centos.org/ works
but when I click on the  link  Special Interest Group on the same page
http://wiki.centos.org/SpecialInterestGroup , the link does NOT work.
I get back

Server not found
          Firefox can't find the server at www.opera.com.

:::important:::
All the examples from above work flawlessly on the MS WIN 7 on the
same laptop, the same ETHERNET cable connected to the same switch hub
with the same router at the same time.
[Reminder: CentOS 6.5 runs on VMWare on WIN 7]


Any hint, FAQ, pointer to RTFM is more than welcome

I am  puzzled, please  help






-- 
"You can't run an economy where the financial sector is making 40
percent of the profits."


        former Fed Chairman Paul Volcker 2009