hi,
there are also the hosts entries that can be added with Spybot S&D, if you added this in the advanced mode, you can select the hosts you want to unblock and delete them from the blocked hosts list.
Hosts that are redirected to the localhost via the hosts file cannot be accessed when the host name needs to be resolved (you can still go there by directly entering the correct ip address). That means that all webbrowsers are affected. Only some Microsoft hosts are exceptions to this.