Browser Issue - Firefox/Safari problem

Hello,

I have been using my MBA for about 3 months. Its been working really well till a few days back. My problem started when i noticed a few days back that my browser was acting up. It has become very slow. I use Firefox and safari, both of them are very slow. They take ages to load websites all of a sudden. My skype seems to work just fine. I went on one of those 'rate my internet websites' and i saw that my downloading speed is around 7mb/s.I read some where on google to close IPv6, but that doesnt seem to work either.

Can some one please help me. I have no idea what to do.

Thank you in advance

 

Any one have any idea????