Firefox 5.0 cannot connect to the Internet after changing the connection from my corporate connection to any other connection. Changing from any other connection to the corporate gives the same problem with the Firefox. IE 7 can connect to the Internet after the changing. Closing and restarting the Firefox allows to connect, but the closing loses all the open pages in the tabs. The network setting is to use the system proxy settings. How to resolve the problem? How to make Firefox not to lose connection, as IE7 does not lose?