Here's a possible fix for Vista SP1 installation failure

[Victek]

Here's a tip that solved my Vista SP1 installation failure problem. The
scenario:

When attempting to install SP1 from Windows Update (or the standalone
installer) the process goes to the end of stage 3 and then says the
installation was not successful, Windows is reverting changes, etc. The
error number is 8004401E, but it's no help. Turns out the real cause was a
couple of missing files:

ServiceModel.mof
ServiceModel.mof.uninstall

These files need to be in C:\Windows\system32\wbem\

In my case the files were on my computer, but in the wrong directory. If
the files are not on the computer they can be downloaded from here:

http://www.enccompany.com/microsoft/windowsvista/sp1/0x8004401E_missing_files.zip

This link was posted by a user in a Microsoft Technet forum (I don't know if
there's an official link on the Microsoft support site for these).

Here are the threads that made me aware of the fix:

http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=3044734&SiteID=17

http://forums.microsoft.com/TechNet/ShowPost.aspx?PostID=3031042&SiteID=17