Also, when you search something in it, Yahoo is the search engine.

Is the browser.newtab.url pref set to your preferred new tab (home) page or do you get the the about:newtab page or another page? See this article about the New Tab page (about:newtab):

• https://support.mozilla.org/kb/new-tab-page-show-hide-and-customize-top-sites

Does the Home toolbar button work as expected?

• Tools > Options > General > Startup: Home page
• https://support.mozilla.org/kb/How+to+set+the+home+page

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem.

• Switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance
• Do NOT click the Reset button on the Safe Mode start window

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

" - An icon for Facebook, Youtube, Twitter, Amazon, Ebay, Google Maps, Google Mail, Outlook, Linkedin Tumblr, Instagram, and an option to add another."

Doesn't sound like you modified the correct preference in about"config or you didn't restart Firefox afterwards. You still have the NewTab page, which will show Search or enter address in the Location Bar until you start typing there. Those "Services" appear when there's no browsing history or most visited page counts saved. That is a controversial recent change to show something other than blank squares when there's nothing in "history". Those Services should disappear pretty quickly and be replaced by "visited sites" as you use Firefox.

Are you clearing browsing history, not saving browsing history, or using Private Browsing mode?

"Also, when you search something in it, Yahoo is the search engine." The same search engine is used in the Location Bar, the about:home default homepage, the New Tab page, the Contextual Menu Search ...... for "text" when text is selected on the page being viewed, and in the Search Bar. The search engine which is selected in the Search Bar is used in all 5 areas.

When started in Safe Mode, my newtab page was back to normal.

I'm not doing any of those things

By "those things" I mean I don't clear history or private browse or anything like that

Okay I fixed it. There was an "astromenda" or something like that at the bottom so I clicked on it and there was an uninstall option. Thanks for the help anyway

Many software updates come bundled with garbageware add-ons or plug-ins that like to make your home page theirs, and your search preference theirs.

Call them Browser hijackers.

Java, Adobe Flash, Adobe Reader, to name a few come bundled, and just about anything you get free from Cnet's "Download.com" (and others) are full of it.

Yahoo, Ask, Conduit search engines (to name a few) often are used to replace your preferred settings, and if anyone does have that pretty New Tab page with the eBay, Tumblr, Facebook, Twitter and others, you have what they refer to as PUPs, "Potentially Unwanted Programs." Your security software, such as Avast! AntiVirus will find these things.