www.panicware.com
My favourite pop-up stopperAs for ad killers, I don't really like them since they never block all as so you still get some when you don't expect it.
If you're feeling adventerous as far as editing Windows settings are, there's something called a HOSTS file which you can edit, I add the names of all ad servers I come across into there (one by one, by hand unfortunately) and make them point to my own PC, so ads from many larger servers never get loaded now since Windows on my PC permanently looks in the wrong place for them (including adserver.gamesquad.net)