>>I saw a demo lock solution that was simple and worked something like this:
>>A file with an expiration date in a character field, with the format:
>>

>>cExpireDate="08.01.2001"
>>if !"."$cExpireDate
>>   * quit
>>endif
>>
>>When the demo opens it determines that the "dots" are still in place, then;
>>dExpireDate=ctod(strtran(cExpireDate,".","/"))
>>if dExpireDate>=date()
>>   repl cExpireDate with strtran(cExpireDate,".","/")
>>endif
>>subsequent re-opens will notice the dots have been replaced with slashes, and
>>not allow the demo to run. I someone hacks the Exiration date field, they
>>will most likely leave the dashes in place, which means the demo will not
>>execute
>
>In this case, the "." vs "/" could have been placed anywhere, even the windows registry, all by itself as a simple flag.
>
>If it's in a file local to the app, and assuming one does backups, or creates a duplicate install, a file compare could reveal what had changed. Some utilities will compare the contents of 2 directories (files and file contents), highlighting all the differences.
>
>But for most cases, it may still be a good solution; one actually winds up looking at the solution, but can't figure out the problem (or vise versa).
Right - and if they're that determined and and the technical where with-all, they could also de-compile it!

Imagination is more important than knowledge