Problem Description :
If you haven’t updated Windows 7 and Windows Server 2008 R2 for a long time, Windows Update can run several hours to detect and to get a list of the updates required.
After installation of KB3138612 please install the following updates inside the Solution Section of this article .
Windows Update Client for Windows 7 and Windows Server 2008 R2: March 2016
https://support.microsoft.com/en-us/kb/3138612
Solution :
Once you try to install KB3172605 you can get the below error message “The update is not applicable to your computer”. If this happens please install KB3020369 first and afterwards KB3172605.
Update for Windows 7 for x64-based Systems (KB3020369)
https://www.microsoft.com/en-US/download/details.aspx?id=46817July 2016 update rollup for Windows 7 SP1 and Windows Server 2008 R2 SP1
https://support.microsoft.com/en-us/kb/3172605
Once installed you can check under “View installed updates” as follows to verify your installation .
Good luck !