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. ---------------- It’s very sad, but many software downloaders/ installers will trick you into installing not only their program, but '''other programs as well. ''' You have heard of the '''fine print in shady''' '''contracts, ''' right? Well, some installers you need to look at the '''itsy bitsy teeny weeny fine print. ''' You are thinking you are giving the installer permission to install the program you want by using the '''recommended''' option. But if you use the '''Manual Option Instead, ''' you discover all kinds of stuff that '''you do not even know what it is or what it does. ''' From now on, everyone needs to '''Use The Manual Option''' to put a stop to this. '''Note''' that these programs can also change browser/computer settings.