Your Extensions list shows;

StartPage 3.4.0.1 ({62DD0A97-FDD4-421b-94A5-D1A9434450C7})

Check its settings

Start Firefox in Safe Mode {web link} by holding down the <Shift> (Mac=Options) key, and then starting Firefox.

A small dialog should appear. Click Start In Safe Mode (not Refresh). Is the problem still there?

How do I access "StartPage 3.4.0.1"? When I go to my extensions page via the gear icon, only 5 extensions are listed and that isn't one of them.

Try disabling everything except your two Adblock Plus extensions.

This is the list next to your post under Question Details > More System Details:

• Adblock Plus 3.0.1 ({d10d0bf8-f5b5-c8b4-a8b2-2b9879e08c5d})
• Adblock Plus Pop-up Addon 0.9.2.1-signed.1-signed (adblockpopups@jessehakanen.net)
• StartPage 3.4.0.1 ({62DD0A97-FDD4-421b-94A5-D1A9434450C7})
• YouTube Flash Video Player 62.0 ({f3bd3dd2-2888-44c5-91a2-2caeb33fb898})
• Webroot Filtering Extension 1.5.0.6 (webrootsecure@webroot.com) (Inactive)

Note: YouTube Flash Video Player is obsolete because YouTube no longer uses Flash.

ok, I must have gone temporally blind. It was there. Disabling that fixed the problem. Thanks.

Good news!

I'll list some optional additional things to consider doing, since a bad extension seldom arrives by itself.

(1) Open the Windows Control Panel, Uninstall a Program.

After the list loads, click the "Installed on" column heading to group the infections, I mean, additions, by date. This can help surface undisclosed bundle items that snuck in with some software you agreed to install. Be suspicious of everything you do not recognize/remember, as malware often uses important or innocent sounding names to discourage you from removing it.

Take out as much trash as possible here. If you're not sure, feel free to post program names or a screenshot of the list.

(2) You can search for remaining issues with the scanning/cleaning tools listed in the previously mentioned support article: Troubleshoot Firefox issues caused by malware. These on-demand scanners are free and take considerable time to run. If they finish quickly and especially if they require payment, you may have a serious infection. I suggest the specialized forums listed in the article in that case.

Hopefully that will flush anything else on your system and in your Firefox that could be a problem.

I am glad to hear that your problem has been resolved. If you haven't already, please select the answer that solves the problem. This will help other users with similar problems find the solution more easily.

Thank you for contacting Mozilla Support.