Hosts file is hidden, so first of all set Folder Options to show hidden files and folders. Then right-click Notepad in the Start menu, and choose "Run as administrator". From Notepad, navigate to the Windows\System32\Drivers\Etc folder, and then choose "All files" from the Open dialog, and you should see it.
It may be a UK only issue, but some good investigative work by members of my ISPs forums discovered some odd issues with the Google DNS servers. I myself was experiencing them, where the BBC News site and a handful of others were either partially loading, or taking up to 3 minutes to load. It was caused by some pretty bizarre routing for some of the page elements IIRC. Anyway, reverting to OpenDNS, which is what I had been using prior to Google, solved all issues instantly.