I found a removal guide for that one: http://malwaretips.com/blogs/bettermarkit-ads-removal/ Please note that I have not tested those steps myself. When the guide recommends using Firefox's Reset feature, you might not realize that you do lose a lot of settings that way. You might be able to avoid that by manually removing unwanted extensions. If you prefer to do that, you can open the Add-ons page using either: * Ctrl+Shift+a * "3-bar" menu button (or Tools menu) > Add-ons In the left column, click Extensions. Then, if in doubt, disable (or if obviously junk, remove). Usually a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step. Any luck?