@Woollcott,
http://help.yahoo.com/kb/index?locale=en_US&page=content&y=PROD_TOOL&id=SLN4727
Uninstall the Yahoo Toolbar
Want to remove Yahoo Toolbar from your browser? See the steps for your browser below.
Mozilla Firefox
In Firefox, click Tools | Add-ons.
Click Extensions.
Select Yahoo Toolbar.
Click Remove.
Restart Firefox.
Microsoft Internet Explorer
In Internet Explorer, click Tools | Manage Add-ons.
Click Toolbars and Extensions.
Scroll down, then select Yahoo Toolbar.
Click Disable.
Restart Internet Explorer.
Google Chrome
In Chrome, click the menu button chrome menu button | Settings.
-The "Settings" window opens.
Click Extensions.
De-select the "Enabled" checkbox for Yahoo Toolbar.
Close and restart Google Chrome.