This is what I do:
Start-Control Panel-Network and Internet-Internet Options-Search (settings)-Toolbars and Extensions (disable or delete the toolbar).
If you're using Vista, you have the additional option of Vista preventing any additional search options trying to be installed on your computer (bottom left-hand corner)
Hope this helps
How do I get rid of the Bing Toolbar and search function. Apparently it installed with some update. It does not show on the Firefox "View - Toolbars" function. I can't locate it in Programs. Running Firefox 3.6.3 on a HP Pavilion Entertainment with Windows 7. I really want to get rid of Bing since it will often send me to search when I use the standard Firefox Toolbar with definitely correct website icons. This never happened before Bing self-installed. I don't like Bing, period!