That link looks like an affiliate link that pays a third party to drive traffic to Yahoo. It could be generated by an add-on.

Let's start here, with the hidden setting for the new tab URL:

(1) In a new tab, type or paste about:config in the address bar and press Enter. Click the button promising to be careful.

(2) In the search box above the list, type or paste newtab and pause while the list is filtered

(3) Double-click the browser.newtab.url preference and enter your preferred page:

• Page thumbnails (default) => about:newtab
• Blank tab => about:blank
• Built-in Firefox home page => about:home
• Any other page => full URL to the page

Press Ctrl+t to open a new tab and verify that it worked. Fixed?

Some gotchas:

If Firefox won't let you edit this setting: you may have something called SearchProtect on your system.

If Firefox lets you save your change but ignores it: one of your extensions may be overriding it. You can review, disable, and/or remove extensions on the add-ons page:

• Ctrl+Shift+A
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then check for anything unknown or untrustworthy.

If the change works during your session, but at the next startup is back to Conduit: you might have a user.js file in your personal Firefox settings folder (your Firefox profile folder). This article describes how to track down and remove the file: How to fix preferences that won't save.

Any luck?

The best thing you can do when everything else is failing is to type about:support into the address bar and click on the button in the top left that says "refresh firefox."

It will not change/delete any bookmarks or passwords, but it will cause your browser to forget all your customizations/add-ons/extensions.

If the Yahoo Search bar is irritating enough for you to do this, like it was for me, and you have every confidence that you can tweak your browser again, go for it.

I tried: Running mozilla in safe mode Deleting a Yahoo add-on that was nowhere to be found Deleting add-ons that might have a hidden yahoo search engine Resetting the "keyword" and other items in about:config Deleting Yahoo and Yahoo related things from Add/Delete Programs Denial Anger Bargaining Begging

And then as I was about to delete my version and lose my bookmarks, I up and found a solution! REFRESH MOZILLA under about:support!