Computer Chat cannot log into facebook-twitter etc...
 

Help computer literate folks
for the last month using my laptop i cannot log inot many site sincluding facebook, twitter or download i tunes.
in firefox i get this message

Quote:
Unable to connect













Firefox can't establish a connection to the server at login.facebook.com.





* The site could be temporarily unavailable or too busy. Try again in a few
moments.

* If you are unable to load any pages, check your computer's network
connection.

* If your computer or network is protected by a firewall or proxy, make sure
that Firefox is permitted to access the Web.

Chrome and IE give similar error messages.
I know its not the network because desktop PC works fine through the same wireless network and modem.

Any thoughts or better solutions.