Check your hosts file for anything different.
Just in case I would do a virus scan.

>I've been using the IE6 Tools\Windows Update menu option and it tries to go to
>http://windowsupdate.microsoft.com/
>
>I try yours below and I get the same result... "The page cannot be displayed." with a message "Cannot find server or DNS Error" at the bottom.
>
>All else of my internet usage is happening normally on the PC.
>
>I just also tried using my W2K notebook and I'm getting the same problem.
>
>
>
>>Try http://update.microsoft.com
>>
>>>I've been trying all day and all I get is an error.
>>>
>>>Has it changed address?