[Ubuntu-BD] Lots of website is not opening

[Sazzad Riyadh]

Assalamualaikum

I installed Ubuntu 14.04 32 bit several months ago. But I faced a problem
from the time of installation. The problem is lots of websites is not
opening. Wesites like: coursera.com, edx.com, addons.mozilla.org,
prothomalojobs.com and many more important other websites. But all these
websites are working perfectly in windows 7. I don't know what is the real
problem. This kind of problem didn't exist while I was using Ubuntu 12.04.
Also the add on pages of mozilla firefox is blank. But in windows I can see
the add ons and install them easily. For better understanding I am
attaching an image.

Please give me some suggestion for solving this problem.


Regards

Sazzad Riyadh