disable registration pg for Release - 1.7.15

I was looking to disable the self registration page outright ( /pg/register/ ).  Is this possible?  I have done a lengthy search on how to disable user registration, but not found a page block type of solution yet.  My production elgg is Release - 1.7.15 and now has been hit with spam bloggers/new users.  The registration verifiaction email doesn't stop them.  I was not planning on going to 1.8.x, since my install seems to be good and I thought going with 1.7.15 would be a stable choice.  I hope there is a solution without specific plugins needed?