Please consider turning on send info to Mozilla before posting a question. This helps us help you. As I have no info from your system that would help see things that cause issues. Since no info no info on Extensions. I do not know of a Firefox Speed checker there are several Extensions with that in it's name so no idea. https://www.google.ca/search?dcr=0&q=Firefox+Speed+Checker&spell=1&sa=X&ved=0ahUKEwjAhe3lsrrXAhVW9GMKHS5GBBwQBQgjKAA&biw=1366&bih=604 Mozilla does not install this sort of thing. You would have had to have gone to the Extension page and added it yourself or it was included in a download. Copy/paste about:addons into the address bar and hit enter then click Extensions Your speed thing should be listed in there. fyi: Mozilla only approves Extensions for use and provides a page for distribution. The Developer of the Extension provides all support and should have support info or a link on their page as well as contact info. Mozilla does try to help with Extensions but are limited to https://support.mozilla.org/en-US/kb/troubleshoot-extensions-themes-to-fix-problems?redirectlocale=en-US&redirectslug=Troubleshooting+extensions+and+themes and asking you to remove it. https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware scan with more than 1 scanner as each uses diff tech. Save the Report. Google everything as do not want to delete something you need for a program. If need help if stuff found https://forums.malwarebytes.com/topic/9573-im-infected-what-do-i-do-now/ Post in 1 forum only and wait. This sorta Extension is for novices as all others go to http://www.speedtest.net/ (sorry) If it is a bother as you say please list proper names of Extensions if come back and also your Firefox Version as have no info. So I can not point you in any direction until you do come back.