|If you are certain it is to do with hosts files then you can disable hosts by going here:|
Simply rename the file Hosts to HostsX and if the problem is there it will be resolved after reboot. Hosts is not essential, it is simply an option that some folk dabble with.
If renaming the Hosts file and rebooting does not cure the problem then it is not an issue with Hosts itself. If the Hosts file comes back again then that could be due to viral activity.
If you actually use Hosts, it is then a matter of finding the websites with which you are having difficulty and (using NotePad) either deleting the associated entries or putting # in front of them. You would then need to rename HostsX back to Hosts and it would be best to set it as "Read only".
some other bloke...