Its an Yontoo ad that installed itself on your computer. Go to the control panel on your computer and uninstall it

I DO NOT HAVE A PROGRAM CALLED YANTOO WHERE DO I FIND IT

I had the same problem. I found a coupon app in a program called "Get It Free". After checking in the control panel, I selected "remove program" and found it. I was then able to delete the app.

I found it in add/remove programs : "I WANT THIS" I deleted it and works fine, Hope works for you .

You have to kill it in two places. FF must be generating revenue from this.

Goto Add-ons

1) Click on the Plug Ins tab.

   Disable both "Coupon Inc" addons.  For some reason I had two.

2) Click on the Extensions tab

   Disable the "Start Now toolbar"

What a pain.