Hate this ..ing images
You entered into my laptop without my permission, I do not know how to remove you.
From the menu bar, click Tools,, then Add-Ons. In your menu bar is not visible, Alt-T will get you to the menu, select Add-Ons (or, Ctrl + Shift +A is more direct). Under extensions,, look for a "Y" in a circle ... the title is "Search and New Tab by Yahoo". Select disable or remove, restart your browser. That's all.