I fixed it!

For me, Virus/malware scanners showed nothing. It turned out to be a firefox extension called XULRunner. I disabled it and the search redirecting went away. The "uninstall" button was grayed out, so I had to do a trick to uninstall it. I ran regedit, then searched the registry for "extensions". For all the firefox extension keys that it found, I looked at the path that it showed. I went to that path, and opened the install.rdf file in a text editor. When I found one that contained the string "XULRunner", I deleted the folder and the registry key. Problem solved!

Thanks a ton, Keithe. This problem popped up for me (along with some other problems), when my system was compromised about a week and a half ago. No matter what kind of scans or cleaning methods I used, my Firefox would always try to redirect me to this ad site from Google results.

I disabled XulRunner in the Add-Ons and the problem seems to be fixed.

However, I think XulRunner isn't inherently the problem. I Googled XulRunner and it seems to be a legitimate Mozilla add-on for something-another.

Is it possible the XulRunner extension was just corrupted by something (e.g.:malware), and can be restored to how it originally was?

yep.... solved the problem. NOW I have a different problem....firefox opens a tab all by itself and keeps going to the same website. I do not have this specific website saved as a favorite. . . . Where is this p.i.t.a. hiding?  :)

I can't believe it, but this worked for me too! Thank you so much!! I thought I was going to have to back to using Internet Explorer.