There's a good chance this is caused by an add-on. Try this: Disable ALL nonessential or unrecognized extensions on the Add-ons page. Either: * Ctrl+Shift+a * orange Firefox button (or Tools menu) > Add-ons In the left column, click Extensions. Then, if in doubt, disable. 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. You may also want to visit the Windows Control Panel, Uninstall a Program, and click the "Installed on" column heading to discover whether you picked up some unwanted additions as part of a bundle. And to mop-up anything not disclosed in those two places, you can use some of the scanning/cleaning programs that other Firefox users have found helpful in this article: [[Troubleshoot Firefox issues caused by malware]]. Does that get rid of it?