From
http://www.fjsmjs.com/IE/hosts.htm
There is a problem with Web accelerator programs. One of the things just
about all of these programs do is save time questioning the Domain Name
Server to find the IP address by putting the domain name and address on a
line in a file in C:\Windows called Hosts with no extension (not Hosts.sam,
which is just a sample file). This File may be hidden, so in Windows
Explorer go to View | Folder Options and, under Hidden Files, click the
radio button for "Show all files". IE then never does a DNS lookup,
trusting that file. This saves a miniscule amount of time until the IP
address is changed. Then IE cannot find the site any more.
Open HOSTS with Notepad and remove any lines referencing the problem Web
sites.
Uninstall the web accelerator. Then open Hosts with Notepad and remove the
line referring to that site. Better yet, if you are not on a network, rename
Hosts to Hosts.old. If you are on a network there may be other lines in
Hosts necessary to proper functioning of the network.
Also see this article:
Troubleshooting Browsing Error Messages in Microsoft Internet Explorer
http://support.microsoft.com/support/IE/ie5/topics/browse/iebrowseemts.asp
--
Frank Saunders, MS-MVP, IE/OE
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