I have created a small but effective way to keep my catering business
costings under control. My employer would like to use this tool for
some or all other units. What I would like to do is to allocate
activation codes to the main workbook to act as licence, these ought to
be time related so to expire and render the program obsolete after 60
day trial or 1 year licence. The question is, can this be achieved
through some very smart vba coding? if so is there a kind soul who is
willing to help me? Many thanks in advance
Alex

Generally it is not worth the effort to implement such attempts. Any code
based attempt is easily defeated by disabling macros, which the user has the
option to do.

You could put your code or critical code in an addin and this would provide
you much more control. You would design your workbook so the addin is
critical for its operation. In the addin you could implement code to check
the date and if it is past a certain date, have the code not perform the
necessary functions.


http://www.microsoft.com/officedev/i...htm#distribute
Distributing Microsoft Excel 97, Word 97, and PowerPoint 97 Solutions (March
3, 1997)

http://www.microsoft.com/exceldev/tips/addins.htm
Protecting the Code in an Add-in


http://msdn.microsoft.com/library/techart/XLCrAddns.htm
Creating Add-ins in Microsoft Excel 97

Here is another article or two you might find useful:
http://msdn.microsoft.com/library/ba...n_addins97.htm
http://msdn.microsoft.com/library/of...exceladdin.htm

You can start with this archive search of methods suggested. Reading these
should give you other words you can search on to find other suggestions.

http://groups.google.co.uk/groups?as...lson&lr=&hl=en

Ironically enough, you can search the same archive to get free code to break
any workbook or sheet protection (not file or VBA code passwords) passwords
you apply.

For File or VBA code, you would need to spend some money at
http://www.lostpassword.com Just to emphasize the vulnerability of any
protection you implement in Excel itself.

Protection is like a padlock. It keeps honest people honest.

--
Regards,
Tom Ogilvy


"alanford" wrote in message
oups.com...
I have created a small but effective way to keep my catering business
costings under control. My employer would like to use this tool for
some or all other units. What I would like to do is to allocate
activation codes to the main workbook to act as licence, these ought to
be time related so to expire and render the program obsolete after 60
day trial or 1 year licence. The question is, can this be achieved
through some very smart vba coding? if so is there a kind soul who is
willing to help me? Many thanks in advance
Alex

Thank you I was somewhat hopeing that it was possible to add a access
code or a combobox which would appear after a time had lapsed and the
user would have to input a code which has to match that which is stored
somewhere either in the form of code somewhere or in a hidden
worksheet. Thanks anyway. Alex

Sure its possible.

You would just use the workbook_Open event. to run the code that checks the
date and otherwise manages your protection scheme. See excel VBA help on
savesetting and getsetting if you want to write to and retrieve from the
registry ( a time or code or both)

see Chip Pearson's page on Events

http://www.cpearson.com/excel/events.htm

for information on how to use events.

It just isn't very effective.

--
Regards,
Tom Ogilvy

"alanford" wrote in message
ups.com...
Thank you I was somewhat hopeing that it was possible to add a access
code or a combobox which would appear after a time had lapsed and the
user would have to input a code which has to match that which is stored
somewhere either in the form of code somewhere or in a hidden
worksheet. Thanks anyway. Alex

Hi Tom,
following on your suggestion I have managed to get the events correct
though I would like to ask you one more favour.

basically I have built some fairly intricate excels workbooks and I
would like to release them, I would though like to allow people to use
them for say 60 days and after that if they like my work and part with
a little cash they can have a code (this could be a alfanumeric series)
that would unblock the workbook. do you think this is possible? if so
how? thank you for your efforts.
Alan