Well, I’ll tell you the main (part) of what security I did for my systems. This was in my all applications developed using Clipper for DOS (singe & multi-user).
I moved to windows development since last 2 years converting my applications one by one from Clipper to VB6, but still didn’t work in the security part for my windows applications, but the security part works 100% and tested well.
This is the idea & you add to it according to your needs:

As soon as I start the application, a security part starts doing the following, it goes to the C: and runs a DOS command (C:\vol), the out put of this command is 2 lines like this:
Volume in drive C has no label
Volume Serial Number is 9785-0FC7
So I capture this out put results and save it to a temp.txt file, then I read this text file and take the last part of the out put (9785-0FC7) and compare it with the one stored some where in my database system, if the serial number matches so the correct computer is running the application if NOT matching so the application has been copied to another PC, so take a security action :
1.Destroy the application files
2.Destroy application security database file (not all data .. only security data)
3.Display an error message to contact the Developer
4.Make a procedure to HANG his computer.
If he restarted the computer, he can’t run the application.

Note:
1.You need to make a small setup program which will capture & convert the (9785-0FC7) to your database installed in that machine.
2. Don't forget to delete the temp file (temp.txt)

HTH


>Thanks for your reply,
>
>Yes, That's I am looking for, could you explain to me in detail please (it is more better if you can give me a simple example) .. thanks a lot in advance..
>
>regards
>Winan