I asked a coworker to find the method/command to run updates on Server Core and he came back with a link to this nice little script:

http://msdn.microsoft.com/en-us/library/aa387102(VS.85).aspx

And every time I forget the command to do something in Server Core, when I do a search to find it, I always come back with a link to this post:

http://blogs.dirteam.com/blogs/sanderberkouwer/archive/2007/08/13/changing-server-core-s-look-and-feel-part-1.aspx

And just because I am lazy, and don't particularly like the command line (even though I like Server Core), I have created a folder with a few batch files that I use when I am setting up a Server Core machine.  For instance, I have a batch file that has the product key in it already and I run it to install the product key and activate. 

I am responsible for keeping a number of machines (around 900 or so) up to date with all the latest Windows Updates.  Recently I noticed that a number (around 15 or so that I am sure of) weren't installing particular updates.  I have seen this in the past, but the particular updates that wouldn't apply weren't of real concern to me, so I didn't really investigate.  The latest updates were of concern though so I started looking into it.  Here are the errors that I am getting:

Description:
Installation Failure: Windows failed to install the following update with error 0x80070643: Visual Studio 2005 Service Pack 1.

Description:
The installation of C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\ZNWF10\VS80sp1-KB926601-X86-ENU.msp is not permitted due to an error in software restriction policy processing. The object cannot be trusted.

As you can see, this particular update is for Visual Studio Service Pack 1.  After a little digging, I found this:

http://support.installshield.com/kb/view.asp?articleid=Q111207

It basically says that there is a problem with the way the local security policy is configured.  When I looked, it appeared that the local security Software Restrictions Policy wasn't configured.  I "added" a policy and put the dot in the "All users except local administrators".  After that the install ran fine.