Ever tried to use your hosts file but it looks like your machine cannot resolve it, you go through search engines, purge and recreate your hosts file, update the registry and find all is not working. Well i faced the same on Windows 7 64 Bit OS.
I found that my OS DNS Client under start –> Run –> services.msc was overriding access to my local hosts file, stopping it fixed this.
Hope this works for you.
// Simon Peter