Thanks for working with me on this.

My IT manager has now resolved the problem which was an incorrect registry entry.
He worked with the document below to find the source of the excel direct launch instructions and did a copy/paste to get the correct information in the registry (all beyond my pay grade)
working with excel direct

The reason the registry entry was corrupt is another matter, but unless it happens again I don't see doing any more work on that piece of the puzzle.

Thanks again!