Hi,
Thanks again for your help. I ran the instructions above, and the cbs.txt file is here (I zipped it up otherwise it would have taken several hours to upload):
https://www.dropbox.com/s/frjoc35sm9z7nua/cbs.zip?dl=0
Meanwhile, I ran another Windows update for some optional updates, and of the 10, 7 succeeded and 3 failed. So there is obviously still some problem in the system. I've just run SFCFix.exe again (after the generation of the cbs.log in your instructions above) and the output of this is now as follows:
SFCFix version 2.4.5.0 by niemiro.
Start time: 2015-09-21 19:59:49.173
Microsoft Windows 7 Service Pack 1 - x86
Not using a script file.
AutoAnalysis::
WARNING: Manifest damage on component "x86_microsoft-windows-security-kerberos_31bf3856ad364e35_6.1.7601.18526_none_e8d560f70f161143". See CBS logfile for more details.
SUMMARY: Some corruptions could not be fixed automatically. Seek advice from helper or sysnative.com.
CBS & SFC total detected corruption count: 6
CBS & SFC total unimportant corruption count: 0
CBS & SFC total fixed corruption count: 0
SURT total detected corruption count: 25
SURT total unimportant corruption count: 0
SURT total fixed corruption count: 0
AutoAnalysis:: directive completed successfully.
Successfully processed all directives.
SFCFix version 2.4.5.0 by niemiro has completed.
Currently storing 0 datablocks.
Finish time: 2015-09-21 20:04:30.684
----------------------EOF-----------------------