I do not know what caused the file corruption as no new software (nor update) had been installed for about a week! It was after editing some PHP scripts that things started to get odd (and those scripts are not even on the same hard drive), first with the editor not closing, then with the Apache server, and so on, and so on ... until I go, for the first itme in many many years, the BSoD...
I should have the Safari browser installed in the next hour or so...