What site is used when you search? Can you post the link to one of the results pages?

Meanwhile, you have two suspicious extensions:

• Royal Raid 2.0.5849.41229 ({bb20fbfe-6fbe-4350-8969-70844d02e0b8})
• Search Quick Know 2.0.5851.3408 ({189a313f-6fc8-4732-a38c-389fd436f212})

Since add-ons can override settings, let's deal with that first. Here's my suggested procedure for tracking down and cleaning up bad add-ons and other hijackers. I know it seems long, but it's really not that bad.

(For Windows Vista, 7, 8, 8.1; XP is somewhat different)

(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 in smoking out 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.

(2) Open Firefox's Add-ons page using either:

• Ctrl+Shift+a
• "3-bar" menu button (or Tools menu) > Add-ons
• in the Windows "Run" dialog, type or paste
  firefox.exe "about:addons"

In the left column, click Plugins. Set nonessential and unrecognized plugins to "Never Activate".

In the left column, click Extensions. Then, if in doubt, disable (or Remove, if possible) unrecognized and unwanted extensions. All extensions are optional; none come with Firefox.

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

Any improvement?

(3) You can search for remaining issues with the scanning/cleaning tools listed in our 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.

The Question Details > More System Details to the right of your post also shows an optional settings file named user.js file in your profile folder (personal settings folder). Firefox uses the settings in that file at startup to override your saved preferences from the previous session.

Unless you created that file yourself, it may contains instructions created by an add-on or external software. You can check and remove the file using the steps in this article: How to fix preferences that won't save.

By default, Windows hides the .js file extension. To work with files as accurately as possible, I recommend showing all extensions. These Microsoft support article has the steps:

• Windows Vista and later: http://windows.microsoft.com/en-us/wi.../show-hide-file-name-extensions
• Windows XP: https://support.microsoft.com/en-us/k.../865219