why has vista stopped automatic updates?

I would think you are right Karen about Updates you already have. You could try reinstalling one to see if it is a revised version? If not, the Installer will let you know it's already there. I haven't looked into why they are listed again. Perhaps they are revised,  prerequisites, or related to the current patches in how hackers can gain access? I have two of the three you note - missing KB975517 and will have to install manually for sure.

This is the first time I've heard of applying Windows Server 2008 patches to Vista - will let you know if I give it a try.

Thanks for your feedback, OUgrad

EDIT - I just tried reinstalling KB4012598 and was told it does not apply to my system - because I already have it.

...an additional 27 updates that I was missing for my Vista 32-bit computer.

They may not be additional ones.  I've checked the patches that were "extra" when I updated Office 2007 and most of them are the same ones that were previously installed a long time ago, i.e., they are still listed in the Update History with a date long before.   Now, they are listed in Installed Updates with a current date!!

In case you are not aware, MS has issued another set of what they consider Extremely Critical Security Updates for both Vista and EVEN Windows XP!!! Here is the link for manual download if you can't get Windows Update to work per VZ's Answer. Scan through all three Tables for applicable downloads.

https://support.microsoft.com/en-us/help/4025687/microsoft-security-advisory-4025685-guidance-for-older-platforms

OUgrad

Dear OUgrad;

Thanks for this information.  We've had a discussion of the five post-April-11-2017 KB files in this advisory, i.e., 4018271, 4018466, 4021903, 4024402, and 4019204) on the m#1 thread .  I had found them earlier by searching through the Microsoft Security Update Summary  using 05/09/2017 and 06/14/2017 as beginning and end dates in the filter to see if the Microsoft Update Catalog showed any patch for the Windows Server 2008 for 32-bit Systems Service Pack 2 with a Vista SP2 x86 version of it.   These five files turned up.  I am happy to hear that there is now a Microsoft Advisory that officially announces the availability of these older-platform security patches.

You might also be interested in the discussion of whether Vista SP2 can be kept up-to-date into 2020 by applying Windows Server 2008 patches.  (See pages 56 and 57 of the m#1 thread).  If you decide to use Windows Server 2008 patches for your Vista machine, I'd like to know how it turns out -- which ones you were able to install and which ones you were not able to install.

Question:

Also, I note that the advisory has two patches that are very old (975517-Oct 14, 2009; 2347290-September 29, 2010) and one that was a month before the last official Vista patch Tuesday, i.e., 4012598 - March 14, 2017);  I have found these three in my Update History and in Installed Updates.    I don't need to install these again, right?

Thanks again.

Edit - changed 4012578 to 4012598 -- Thanks OUgrad for catching that.

In case you are not aware, MS has issued another set of what they consider Extremely Critical Security Updates for both Vista and EVEN Windows XP!!! Here is the link for manual download if you can't get Windows Update to work per VZ's Answer. Scan through all three Tables for applicable downloads.

https://support.microsoft.com/en-us/help/4025687/microsoft-security-advisory-4025685-guidance-for-older-platforms

OUgrad

EDIT - Here are the June 13, 2017 Office Updates, including Office 2007 and 2003.

https://support.microsoft.com/en-us/help/4023935/june-13-2017-update-for-microsoft-office