DST cumulative time zone update

KB981793 This update supersedes and replaces update 979306, which was released in February 2010. This update also includes additional time zone changes that were signed in to law after update 979306 was created.
May 2010 cumulative time zone update for Windows operating systems
http://support.microsoft.com/kb/981793
Here's a list dating back to 2007
http://support.microsoft.com/search/default.aspx?mode=a&query=DST+cumulative+time+zone+update&spid=global&catalog=LCID%3D3081&ast=25&ast=28&ast=30&ast=31&res=10
Does that help you?

Unfortunately no.  The update you referenced is not showing in the add/remove program list. (see attached)  I haven’t seen it before but is it possible for an update to be installed but not show in this list?  Where else could I look?

Look also in C:\Windows

You should find most, if not all, of the updates in there. They all start with $NTUninstall

I checked there and used the search feature (including hidden files) but couldn't locate 981793

Some updates are over written
 download and run >WinUpdatesList
displays the list of all Windows updates (Service Packs and Hotfixes) installed on your local computer
http://www.nirsoft.net/utils/wul.html

just incase
the actual download near the bootm of the page, they want you to read thier detials first
Download WinUpdatesList in zip file  
Download self-install executable of WinUpdatesList  

The actual issue was that this update was installed

update KB2443685, December 2010 cumulative

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