Never download anything unless you know what it is and does. And only download from reputable websites. If you are not sure of something, do a web search. ----------------- Let's make sure your system is clean. You may have ad/mal-ware. Further information can be found in this article; https://support.mozilla.org/en-US/kb/troubleshoot-firefox-issues-caused-malware?cache=no Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.