I have a client who was experiencing a similar problem and I used the following method to bring the Windows Update site back to life:
The two caveats that need to be mentioned are:
1) He's also got Mozilla Firefox installed on his computer, and
2) He's was using Internet Explorer 6
So if one or both of these pre-requisites might fit your situation, then try the following:
Go to Control Panel, Internet Options, and use the Programs Tab to make IE your default browser. It can be done in a couple of different ways depending on whether you're using IE6 or IE7, but it's pretty obvious what to do in either case.
After making IE6/7 his default browser, the Windows Update site came right up.
It seems that, while it appeared to be using IE to go to the Windows Update site, it was actually using Firefox and couldn't talk "ActiveX" to get the Page to show properly.
Additionally, after upgrading to IE7, I used the Reset Button on the Advanced Tab in Internet Options to clear up a few issues having to do with other ActiveX Plug-ins, and started reinstalling miscellaneous ActiveX plugins as needed, such as Flash Player, etc.
Let me know if this helps.
Regards to All