Google/search redirect virus that I can't locate- please help!

For the last few days, all of my searches, whether in google or yahoo, are taking me to bogus pages when I click on the links in the search results. this is happening whether I use IE, firefox or google chrome. I updated my norton and ran the full system scan for viruses and all it found was tracking cookies. I chatted with norton support and they suggested that I use the Norton Power Eraser, but I'd read things on here suggesting that that wasn't such a good thing to, probably especially not for someone like me who isn't super computer savvy. Can anyone give me some direction on what to do? I'm running Windows 7.