>>Hello Hilmar,
>>
>>If you find a solution (either here or elsewhere) to this problem could you please let me know about it. I do the same thing with an app.
>>
>>Thanks.
>
>Such a solution seems to be quite elusive; so far I have seen the following problems: (1) higher security settings in Windows 7 - the reason I started this thread, and (2) virtual machines, as mentioned in this thread, are a new problem I hadn't seriously thought about before.

Sometimes it is possible to test if running in a virtual environment. I wrote some VFP code years ago to test for running under VMWare sucessfully because the VMWare shell had certain characteristics that gave it away. There are probably similar ways to detect other virtual machines. But you should rather ask yourself who are you trying to protect yourself from becuase against serious crackers you will have no chance anyway - they will crack the VFP code and remove any checks you put in there.