This is similar to what happened on my old laptop. The original HP discs were damaged, so I installed windoze from a normal retail pack, but using the PROPER registration key for my laptop (so I was still using a licensed version). It did install properly, but every time I tried to update, MicroMush sent Gill Bates to my computer to warn me about piracy, just as you are experiencing.
So, I can tell anyone you don't need to be a cut throat pirate of the computer to get this.