I have seen popup blockers that instead popped up a different pop-up or installed adware/spyware on the system after it was installed. I usually am called to clean that junk off the computer of whomever I know that installed it.

If you want to block pop-ups, use Mozilla and turn off unrequested windows, etc. The problem is that some web sites will refuse to serve pages if they detect that you blocked pop-ups.

The best way to block pop-up ads is to edit the hosts file to route the spammer's host to 127.0.0.1 and then close the empty window. It is free and can block all traffic from that domain.

As for the service pack blocking pop-ups, I am from Missouri, I have to see it in action before I can believe it.