Date Triggered Decay

[JohnL11935]

I build hospital finance models that are distributed among various users, both within and without my local office. The models contain multiple worksheets with names that vary depending upon the topic. I've recently discovered the models are being distributed to and used by unauthorized staff and consultants.

I would like to develop a way of whenever the model is opened, say 60 days past a predetermined date, that a macro will automatically run that will delete the most pertinent worksheets and then save the file so it is no longer usable.

My thoughts were to place in an out of the way cell (on each worksheet if necessary) an 'if statement' using something along the lines of =IF(TODAY()-Update_Date>60,"Run Macro","Wait") Then have the results of the formula start the macro.

First of all, is the idea of a "time decay" a viable means of limiting access to my models?

I understand the model would need to be being read off of some writable medium in order for this to work (no CD/DVD). I am also wondering if someone simply has to have their security setting set high enough that the macro would be unable to run.

If you believe this idea won't work can you suggest some alternative security measure? I know 'Excel' and 'Secure' don't usually belong in the same sentence but I would like to at least make it as difficult as possible for them. I could also place these 'if statements' on a password protected sheet for some extra added frustration.

If you believe this idea would help can you get me started on the code necessary? I've been referencing Walkenbach's Excel 2000 Power Programming with VBA but the extent of my experience is strictly limited to recording macros.

Thanks.


.