Was 0x8ddd0009, now just ends in blank page

WinXP Pro SP2 + all updates until this week.

I was getting the 0x8ddd0009 after a long time spent in WU looking for
updates. Somewhere along the way doing most all of the voodoo from this
group and elsewhere on the web (downloaded the latest WU patch, MSI 3.1v2,
reregistered a bunch of DLLs, dumped all the TIFs, tried as a different
admin user, checked the clock, tried lots of times and at different times of
the day, removed SoftwareDistribution and CatRoot2, multiple reboots, tried
with firewall off, etc.) the problem changed to WU running for upwards of an
hour, near the end IE and most of the rest of Explorer, et al., including
things like screensaver become pretty comatose, then the WinUpdate web page
just goes blank. No errors, no text, just the dressing at the left and the
top (painted for the first time in half an hour or so) and a big white frame
of nothing.

Any thoughts of where to go next? Any point in opening a support case?

I'm in the same boat. Done everything you indicated and a few other things.
However, my problem is on a W2K3 server.

I did manage to get the Windows critical updates to install by using a
combination of the Baseline Security Analyzer and reverting to the Windows
Update site as opposed to the Microsoft Update site. However, I still need to
get the other updates as my server runs some Office automation processes.

:-(