ON IE 9 click the tools in top right corner then "Manage add ons".
Click Toolbars and extensions tab. Highlight if listed then disable and delete.
If not under Toolbar tab click "Search providers" tab if listed highlight then disable and delete.
Tricky suckers like to hide that junk.
Chrome is similar. It will be listed under Search or Toolbars.
FF and Opera I have no idea.
That is how I had to get rid of one that snuck in on me.
Let me know if you find it there.
Added info here.> Remove Alot Toolbar