Ta, CIII, but not much help there, I'm afraid. I had been through most of that and only restoring the C:\Windows\Installer\{91140000- blah blah fixed it.
Now I know that repair will not run with USB3 I should be better placed for the next puzzle!
Why the file was 'disappeared' I have no idea.
Last edited by BOAC; 22nd April 2014 at 16:29.