Hi Mikej1,
Welcome to Microsoft Answers community.
a) Did you make any changes to the computer recently link installing/uninstalling/upgrade?
Reset Windows Update components and then try installing the update.
To reset Windows Update components visit the below link and click on Fix it button/follow the troubleshooting steps do it manually.
http://support.microsoft.com/kb/971058
If the above method fails then download windows installer cleanup utility form the below link and run it. It will cleanup the installer program, so that you will be able to install the programs easily. Now try updating KB974810 and KB974234.
The Windows Installer CleanUp Utility is provided "as is" to help resolve installation problems for programs that use Microsoft Windows Installer.
http://support.microsoft.com/default.aspx/kb/290301
If the above methods fail the manually download the updates from the below link and install it. I would suggest you to right click on the downloaded file and select Run as Administrator to install it.
For more information visit the below links:
http://support.microsoft.com/kb/974810
http://support.microsoft.com/kb/974234
Hope this information is helpful.
Let me know if this worked.
Thanks and Regards:
Umesh P - Microsoft Support
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