Default search engine keeps switching to Yahoo
I use Firefox, Chrome & Safari as network browsers. Suddenly, all of them are defaulting to Yahoo as the search engine. If I go into prefences and change it back to Google, it switches back to Yahoo immediately. It also switches my home page to Yahoo on all three browsers.
I recently installed new 3D software critical to my workflow, so I'm guessing that that has something to do with it, but I have no idea how to track this down.
Any help?
Mac Pro, Mac OS X (10.7.3)