Garry, their are two ways.  1. Tools Options General and change your search 
provider.  2. Tools add ones and disable or remove the bing add on.
If the bing or any other tool bar has been installed, I remove it with revo 
uninstaller.
That is available from
http://www.savemybutt.com  in the download section.
I leave Revo at the defaults for everything, and that has been good enough. 
It is much more thorough than add remove programs from the windows control 
panel, but you can try that first and remove any tool bar you find. 
Toolbars are the new way of paying for free software, so they often get 
installed invisibly.