If it can be viewed, listened too or played, it can be copied. There is no one hundred percent safe way to protect anything from being copied.

As an example, though not for software, take the new HD protection scheme, HDCP. There are already devices which can easily remove protection from a HDCP stream, and the technology isn't even really rolled out yet. True, the key could be revocated, but how likeley is it that anyone will really push the big red "NO DVDS FOR YOU!" button.

Software copy protection can be more efficient obviously, but even the super ultra highest level of copy protection can and will be broken. (See starforce)

So here's a question: Why even bother? Why do big companies try to copy protect their games? It only costs money and doesn't help anyways, so they might as well stop trying and just pocket the money they would spend on copy protection. If they still wanted to fight piracy, they could spend the money on finding crackers and sueing them big time instead.