u must search.. (not sure but think on ron de bruins or chip pearson
name/site)

u can very hidden all sheets accept one. with a macro that tells the
workbook to open all very hidden sheets if macro is enabled. in that case it
will go and check the date for self destruct. if macro's disabled u will not
be able to see any of the sheets in any way.

i never used this before but by sounds of it look like something u could
use. i found it by searching the posts here. then u will find a link to a
web page.


something they state clear though is that no matter what u do it can be
cracked.....

i downloaded some example workbooks from the site with expire codes etc.