Anyone knows a good software protection method against software illegal reproduction?

We have looked at Hardlock from Aladdin that seems pretty good but we did not physically tried it. If anyone has some experience with this method I would appreciate some real life feedback about it.

We have also read some info on the Web on PC Guard for DOS.
This one do not need any physical module to be installed but reads the computer signature on the first installation. We like very much the principle but it need a standalone .EXE and we do not use standalone .EXE with Foxpro 2.5b because that would be too much work to retouch the source codes all over since there is a flaw with macro substitution.

Since we began to sell all over the world, this is a must and for very soon.

So, every advise or experience from anyone is very welcome.

Thanks in advance.