Separate Issue; Your System Details shows;

Installed Plug-ins

Norton Safe Search 3.0.1.13 (nortonsafesearch_ul@symantec.com) Norton Safe Search 3.0.1.14 (nortonsafesearch_ul_2@symantec.com)
Having more than one version of a program may cause issues. You must remove the older programs. Then get the current full installer.

The problem could be caused by adware, an installed add-on, or an installer program.

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.