Firefox Connection Issues on High Traffic Sites

I tried accessing Google, Yahoo, Bloglines Facebook and a host of other sites and Firefox will not connect, but it works just fine on other sites like Mozilla. I have uninstalled the most recent version, downloaded a older version and checked Firewall setting but nothing is working.

Oh, I even tried some cleaner that claims to locate spyware in Firefox but it said it was clean. Also ran Malwarebytes.

help?

 

Vundofix was the cleaner which seemed pretty useless. I use CCleaner all the time.

IE was working fine actually. I finally deleted all the cookies for the sites I couldnt connect with in FF. Its not running great, but its running.

I will try and follow the steps that I did not take from the link you , thanks again!