Was it Q322289? If so, it has caused some ASP.NET services to fail. Here's a
post from an MS support person about what to do:
"We have seen an ASP.NET issue coming up here in the newsgroup and within
Microsoft resulting from the installation of the update explained in
Q322289. To be specific we see that ASP.Net pages will not serve directly
after the patch has been installed.
Most of the issues have been resolved by simply reinstalling but, here are
the basic steps that we suggest you try. As we receive more information we
will post a Q-Article.
1) If possible uninstall the patch from add/remove programs
3) Re-apply the patch
If you do not have an entry in the add/remove programs then:
2) Re-apply the patch
On Friday, I installed the "ASP.NET State Server Mode, English Edition"
update from the Microsoft Critical Notifier". Since then, I can't get
debugging to work in ASP or ASP.NET and I can't get ASP.NET application to
work at all! I have not been able to work around it yet. If you know of a
fix, please let me know.