Type about:addons<enter> in the address bar to open your Add-ons Manager. Hot key; (<Control> [Mac=<Command>] <Shift> A)

In the Add-ons Manager, on the left, select Extensions. Remove “ Yahoo “ Anything.

Also remove SafeSearch, SearchAssist Incognito, FileConverter Addon, SearchLock, DiscreteSearch, WebSearch, Findwide Search Engine, securedsearch

Now do the same in the computer’s Programs Folder.

Windows: Start > Control Panel > Uninstall Programs. Mac: Open the Applications folder. Linux: Check your user manual.

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.

Thanks Fred, but if I enter about:addons it opens a blank page? as I said in my comments I can't open add ons at all? if I go to them from the three bars, it just opens a blank page.

I did a complete refresh to Firefox, and kept my bookmarks etc, that cleared the problem, even my CPU gauge on my front screen returned? someone said it could have been a PUP? whatever that is.

Thanks!

That was very good work. Well Done. Please flag your last post as Solved Problem as this can help others with similar problems.

Thanks Fred! Solved Problem!

Glad to help. Safe Surfing.