I fixed this issue by going to Firefox button -> addons -> extensions and removing the StartNow toolbar. I also went to add/remove programs in Windows and uninstalled it there. It came from Cnet (download.com). Hope that helps. It fixed mine (finally).

If you accidentally install StartNow toolbar aka Bing Bar, as I did you have to do several things to get rid of all the effects it has, damn MS, first as stated above uninstall Bing Bar from Add Remove Programs, next Tools=> add-ons => extension,s uninstall StartNow, and finally not mentioned above, you have to go to the Firefox config file, type about:config into the url field and go, in the config file get rid of all references to Bing and MSN, you can find them by using the filter.