Seems like your computer is infected with virus. One way you could fix this without purchasing an antivirus is to reset firefox. You may create a backup of your firefox before doing it. This will reset all your configurations including history and plugins. The Refresh Firefox feature can fix many issues by restoring Firefox to default: mzl.la/MnSTZB Before that, I'd suggest you to try deleting all the previous plugins and toolbars you've installed.

Security Issue: Update your Flash Player Note: Windows users should download the active_x for Internet Explorer. and the plugin for Plugin-based browsers (like Firefox).

Note: Windows 8 and Windows 10 have built-in flash players and Adobe will cause a conflict. Install the plugin only. Not the active_x.

Flash Player Version: 23.0.0.162 Flash Player (Linux) Version 11.2.202.635

https://get.adobe.com/flashplayer/ Direct link scans current system and browser Note: Other software is offered in the download.

https://get.adobe.com/flashplayer/otherversions/ Step 1: Select Operating System Step 2: Select A Version (Firefox, Win IE . . . .) Note: Other software is offered in the download.

See if there are updates for your graphics drivers https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration

You may have ad / mal-ware. Further information can be found in the Troubleshoot Firefox issues caused by malware article.

Run most or all of the listed malware scanners. Each works differently. If one program misses something, another may pick it up.

Note: A Firefox reset may not remove any bad programs.

After your system has been cleaned, Bookmark and use this; Download the Mozilla Search Reset {web link} This add-on is very simple: on installation, it backs up and then resets your search preferences and home page to their default values, and then uninstalls itself. This affects the search bar, URL bar searches, and the home page.