How to remove/change automatic Yahoo! search from the Firefox ADDRESS bar?

This was making me crazy, but not enough to pay a Yahoo! expert to solve it for $18.  I searched Google: "in Firefox address bar yahoo comes up with results how to change it." …and VIOLA!  an answer that works.  

I have never had any Yahoo add-ons, that I was aware of and it seems to have sneaked in somehow.  I'm a member of a few Yahoo groups, but hadn't noticed any "tools" installed, except this one annoying thing. There was nothing in my add-ons or plug-ins.

This is only for Firefox, as that seems to have the issue:

Step 1: Open a new Firefox browser window.
Step 2: Type about:config in the search field and press Enter.
Step 3: Click the "I Will Be Careful" button if necessary.
Step 4: Scroll to find a configuration key titled: keyword.URL
Step 5: Select "keyword.URL" and right-click, then hit "Reset" from the drop-down menu.

Thank you, Kalea, for this easy step-by-step.  Solved it instantly!