Changed Hosts File / Cannot Connect To Internet

I followed the instructions on this page: url...I renamed my hosts file "hosts.orig", downloaded, unzipped, and saved another hosts file from url... named HOSTS in the same place as the original. After that, I couldn't connect to the internet at home or at the library. I tried deleting the "new" hosts file that I downloaded, in order to put things back to how they used to be, but any time I try to do something to the "HOSTS" file I get a pop up saying: "The action can't be completed because the file is open in Cryptographic Services.... close the file and try again" which doesn't work. I tried stopping the DNS thing, but that only worked for about 5 minutes. I restarted the computer because it was slowing down, and the DNS thing restarted itself, and the internet disconnected again. I try stopping it, but an error message saying "Windows could not stop the DNS client service on local computer. error 1053: the service did not respond to the start or control request in a timely fashion"