Please update to 57.0.2 https://support.mozilla.org/en-US/kb/update-firefox-latest-version Well.....I run Malwarebytes and it would not even load the page as is marked Malicious. So I would hope this makes you a little more aware of what your installing. If want to know about a file before you open it or a URL go to Virustotal.com Please use more than 1 scanner as each uses diff tech : https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware Save your Report and google each before deleting anything as do not want to delete something you need, If need help : https://forums.malwarebytes.com/topic/9573-im-infected-what-do-i-do-now/ Post in only 1 forum, then wait. Please let us know if this solved your issue or if need further assistance.