browsers doesn't display web pages without proxy

[bmcm]

I have a dsl cable internet connection and I use proxy sometimes. Recently my browsers couldn't open any webpage without activating proxy. I used to ping some domains and I got replies and I looked at proxy setting in any browser and choosed no proxy , but when I try to open a website It says for example could not locate the remote server in Opera , and after using proxy server (like your freedom) and activate my proxy setting in browsers I can easily open any webpage.
how can I solve this problem?

 

[roncerr]

Judging from your time zone, you may be in a part of the world where websites are blocked. Do other people where you are also need to use a proxy for the same sites you have tried?