Follow up - successfully installed 14.04 on VBox (Win 7 x 64 base) after dropping the amount of memory required and turning off load 3rd party apps as both these are mentioned as possible causes, above. Don't know which one did the job but it is now a working system.
Follow up - successfully installed 14.04 on VBox (Win 7 x 64 base) after dropping the amount of memory required and turning off load 3rd party apps as both these are mentioned as possible causes, above. Don't know which one did the job but it is now a working system.