Firefox can get onto yahoo however whenever I use the search function is says link is broken. Equally cannot access google either. Thanks

Firstly I have had to changed my home page because google will not load. Then I can get access into yahoo itself, mail etc but cannot get any of the search engines to function. All other websites ok apart from when trying to do searches!            
       

   *   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.

The connection has timed out The server at uk.search.yahoo.com is taking too long to respond. Firstly I have had to changed my home page because google will not load. Then I can get access into yahoo itself, mail etc but cannot get any of the search engines to function. All other websites ok apart from when trying to do searches! The yahoo search shows the following message or it indicates that the connection has broken. Tested internet connection and all ok! Any advice appreciated. * 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.