Depends on the program. The only way that I have done it is to have the user register their company name with me. Then they get a key code which is a calculation from their company name. At every opportunity throughout the program place their company name (eg; every report, some screens, startup screen 'This program is licenced for use by XYZ Ltd.').

This works for my accounting programs. I have the full programs available to download from the net (www.trader.co.nz) where people can use them with the name of 'DEMONSTRATION PROGRAM ONLY' except that with that name the user can't perform some serious processess (like end of month) and some limited file sizes.

This has the effect of the user being able to try it out and see if it'll suite before purchase.

Sure there are some systems out there where Fred Smith is using Joe Blogg's registered program (may they burn in hell), but even then they are limited to what they can do. It's embarrasing to show their accountant the reports or to let others see the screen with someone else's name on it - and they can't send out invoices cause it'll print Joe's name on it.

The calculation must be hard to reverse engineer with as many low level calls as necessary, otherwise you'll get what I got when I started out - a computer club selling registrations of my program to dealers to raise money for an outing!

Steve

>I'm really looking for a simple way of ensuring that only customers that have paid for and registered our applications, can actually use them. Something similar to the way shareware works - an expiry date - an opportunity to enter a unique license number based on the company/user name.
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>Rgds
>Petras