Hi,
That was pretty sloppy on your ISP's part, effectively they installed a Black Router, they didn't do their homework when setting it up.

>Well the final solution was very weird, in my opinion.
>
>The "solution" was the "MTU" value!!!
>
>I had seen references to this in some Google results and had tried the values 1492, 1480 and 1468, all to no avail. So I assumed that wasn't a factor.
>
>After talking with my ISP again and going through a host of things, access to micrisift.com was finally achieved by bypassing the route and going directly. But that didn't sit well because I had reset the router to factory settings before calling the ISP, so I didn't see how it could be implicated.
>
>Anyway, I went out to buy a replacement router (should have been cheap enough for a regular wire-only version) but on the way there I had second thoughts, so I came home and called the ISP again. I wanted to know what ELSE is different when I connected 'directly', bypassing my router. He said nothing is different. But then he said they had been discussing the issue and others like mine (for differing web sites) had come in and that sometimes a MTU of 1400 lets it through. So I tried that while he was on the phone and I got through!@!#@!
>
>Turns out they had "upgraded" a major piece of equipment 2 weeks ago and calls like mine started coming in. They weren't yet that far into diagnosis(!!!) but the MTU had worked for a few users.
>
>I eventually got up to a value of 1440. Anything higher prevented access to Microsoft.
>
>I have no idea WHY!?!?
>
>I hope this helps the next person.
>
>
>>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?