Looks like you have a big clean up job to do on your system. Read through the steps at the link, printing the page will help you not miss any of the 23 steps to clean your computer.

https://www.bleepingcomputer.com/virus-removal/remove-www.navsmart.info-browser-hijacker

If after following all the steps in the instructions your computer is still infected you should join/log-in to bleepingcomputer and post for help in their malware help forum.

My computer was infected a few years ago with a different malware and the helpers at that site guided me through cleaning my system.

Also, check out 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.

Separate Security Issue: Update your Flash Player Note: Windows users should download the ActiveX 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 ActiveX.

Flash Player Version: Version 27.0.0.183

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

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. <Windows Only> +++++++++++++++++++ See if there are updates for your graphics drivers https://support.mozilla.org/en-US/kb/upgrade-graphics-drivers-use-hardware-acceleration