It is possible that you use a proxy... Go to this in internet explorer: Tools > Internet Options > Connections > Click on whatever it says in the list of connections, then click settings. Here, check if "Use a proxy server for this connection...." is checked. Note: if you use broadband, instead of choosing something from the list and clicking settings, just click LAN settings instead. If you do use a proxy, then I'll explain how to set it up in firefox (it takes about 2 minutes), but if you don't, I don't want to bother typing instructions.