I have been trying to figure out how to fire a function when a workbook
is opened.

I have been directed to workbook open event, I have found many examples
that will work except they are limited to working only when a
particular workbook is open.

For example I have the APPEVENT.xls file (I believe via Chip Pearson's
site) which essentially does what I need, except that it only works if
APPEVENT is open. If APPEVENT is closed and I open another workbook,
the code does not fire.

Seems to me this is because there is code specifically in the
ThisWorkBook module to make it all happen. I cannot (by the nature of
the issue at hand) put this code in every workbook (we get a workbook,
makes updates, these updates are then uploaded into access, and then
re-exported from access the make a new updated workbook.)

So if I understand this all correctly, I need to put the code that is
normally put in the ThisWorkBook module, into a module on my addin.
Except that everytime I do that, nothing will happen at all.

So how can this be made into a truely application level process, that
does not rely on ThisWorkBook to function? Or am I wrong in my
assumptions.