Unfortunately there is really no exe starting, including regedit.exe, so
this fix doesn't work for me. It's that frustrating.
In the meantime I have found a 'rescue CD' which seems to boot some kind of
tiny Windows dialogs where I can start a DOS box (CMD). There a drive X: was
shown as home drive, and my original drive C: was now D:, and when I
switched to this drive D: I could start a Regedit.exe, but I'm not sure if
the registry it will access then belongs to the hard disk system C: or to
the temporary CD system on X: - I'm not at home now and so I cannot test the
kb fix immediately.
Ralph