I have a similar problem to http://www.bleepingcomputer.com/forums/t/271417/google-redirect-both-ie-and-firefox/
When I search in Google and click on a link in the organic search section I occasionally get redirected to another site. At first, I was being redirected to various Clickbank products. I did some research and found it was always a hoplink with a certain affiliate code. I alerted Clickbank and they have closed that account. But I'm still getting redirected, it just goes to an error page from Clickbank stating that the account has been closed or disabled. I also get redirected to Amazon. I'm assuming that it's probably the same guy.
The redirects happen randomly (not every time). I use Firefox 3.5.5. I'm also using TrendMicro Internet Security Pro 17.1.1250 with the latest updates.
I've run full scans with both TM and MalwareBytes, but neither find any problems. I don't see anything that pops out in my HighJackThis Log.
Usually, I can find and remove these things on my own, but this is over my head. I'm stumped. I've seen other posts with similar problems that point to it being a rootkit and that's a little beyond my level of expertise.
Please help. Thanks