Ok, I know what to do now. I just had to be sure:
- Click the Yahoo icon/down arrow button
- Choose "Manage Search Engines..."
- Select "Yahoo"
- Click Remove
However, if this doesn't work or if the Yahoo search engine is not in there, then we'll keep at it until we get rid of it.
You can also switch between search engines with the keyboard shortcut
Ctrl+K, then use your up and down arrow keys.