Installing KB938444 - Microsoft SharePoint Team Blog - Site Home - MSDN Blogs: "We’ve been tracking a small number of customers that have experienced issues after installing KB938444 through Windows Update.�
After the reboot at the end of installation we’ve had reports of Windows SharePoint Services sites and Central Administration being inaccessible with the error, “HTTP 404”, “Server Error: …” or “Cannot connect to the configuration database”.
This issue only affects Windows SharePoint Service v3 standalone installations that use the Windows Internal Database (wYukon) and does not affect SharePoint or user data.�
If after applying KB938444 you hit one of the errors described above you will need to run psconfig from an administrator command prompt as detailed below to complete the update.
psconfig -cmd upgrade -inplace b2b -wait –force
The Windows Small Business Server team have a blog post detailing this, and some other SBS specific steps, that relate to this issue here (By default SBS ships with WSS configured to use wYukon).
KB938444 is an important security update and we recommend installing it as soon as possible."