You can do that. The problem is that it's trivial for anyone with enough
savvy to find these newsgroups to bypass any Excel protection you
install, so your code that writes to the registry would be easily
modified/disabled.

If that's not a concern, I've got some examples of sequential numbering
that could be modified for your purpose he

http://www.mcgimpsey.com/excel/sequentialnums.html

The best way to do it would probably to compile your application into a
COM add-in that tweaked the registry or a hidden file.

In article ,
Ed wrote:

Hi
I don't really understand your reply so, I think my question was not stated
clear enough.
An example of what I am referring to is -
Once I installed a game that would be inoperable after 30 days.
After 30 days, I reinstalled the game and it was still inoperable.
So, the original operation of the game put information in some file in
the
computer to let the reinstalled game know that the 30 days of usage was
already used up.
In other words the game entered a message in a file (other than the game
file, such as the registry file or one of the ini files) that the 30 days
have past. Then the reinstalled game sees this message and stops the game
from working.
This is what I am trying to do in my Excel spreadsheet Macro procedure.
Thankyou,