You power cycled the modem and router and restarted the computers?

You have a D-Link router right? Setup/Internet, at the bottom;

Primary DNS Address :
Secondary DNS Address :

I use Google's, partly because they are easy to remember,, but they seem to work well. My ISP's DNS servers suck, they don't automatically put the .com in for example, instead they take you to a search results page of theirs so you can give them a click, and the .com site I was going to sometimes isn't even listed till farther down rather than the first choice or so.

Remove the, addresses from your network prefs, let the router handle DNS.