Presumably you are doing a time limited demo of your app....

If you're distributing your app using Package & Deployment wizard or something like that, your files will have the installation date stamped on them as their creation date.

you can use the FileDateTime function to extract this stamp

You could then use the DateAdd function to calculate when the program is to expire, eg to see if it's more than 30 days since installation, use

Code:
IF Date > DateAdd (d,30,filedatetime("FILE.EXE")) then
I've not tried this code, so it might need re wording slightly!

PS, I wouldnt have a clue how to stop a file being copied, though