Where does it appear, exactly? Does it add toolbar area controls, show pop-up windows, add itself into web pages?

Some extensions cloak themselves. To deactivate cloaking, you need to look for them in Firefox's Safe Mode. That's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: Diagnose Firefox issues using Troubleshoot Mode.

You can restart Firefox in Safe Mode using

Help > Restart with Add-ons Disabled (Flash and other plugins still run)

In the dialog, click "Start in Safe Mode" (not Reset)

Then recheck the Add-ons page, Extensions section, for any additions. Please do not assume that something with a benign-sounding name is okay; if you aren't aware that it is actually valuable to you, consider removing it.

When there is no Remove button, you usually will find an entry in the Windows Control Panel, Uninstall a Program. Clicking the "Installed on" column heading can help in investigating bundles that sneak adware onto your computer along with something free that you actually wanted.

Note: To exit Safe Mode and return to normal, just close Firefox and start it again.

Before I got your answer, I read about a reset thru troubleshooting. I did that, and now Firefox has completely changed. No more drop down menus, google searches are untrusted? My bookmarks are under the gear on the upper right corner. My comfortable Firefox is gone. I have a profile folder on my desktop. It did get rid of jollywallet.

How do I get back to drop down menus? How do I get google to be trusted? Bing searches work. What do I do now?

Okay, this is a little more complicated now.

Firefox stores your settings in a folder which it terms a profile. You can have multiple profiles, but only one running at a time.

When you use Reset, Firefox creates a new profile for you and copies over your bookmarks and selected other data.

At this point, you have a choice: do you want to build up your new profile with your standard customizations, or do you want to resurrect your old profile and try to clean it?

I guess it's not really a choice because you can do both and switch back and forth deciding which works better for you.

Here's my suggested old profile resurrection procedure:

Overview

These are the steps:

(1) Create a new Firefox profile
(2) Remove everything from that new profile folder
(3) Copy in everything from the old profile folder

Create a new Firefox profile (Windows)

Exit Firefox and start up in the Profile Manager using Start > search box (or Run):

firefox.exe -P

Note: Any time you want to switch profiles, exit Firefox and return to this dialog.

Click the Create Profile button. Use the default location (i.e., do not click to choose a different folder). Then select that new profile in the dialog and start Firefox.

Open the New Profile folder in Windows Explorer

Firefox in the new profile should look like a factory fresh installation. Open the Troubleshooting Information page using either:

• Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table, click the "Show Folder" button. Firefox will launch your brand new profile folder in Windows Explorer.

Leaving this folder open, switch back to Firefox, and Exit. This will leave that profile folder open in Windows Explorer.

Copy Old Data in Place of New

In that new profile folder, select all the contents and delete.

Leaving that window open, open or switch over to your Old Firefox Data folder. Drill down into your old profile folder. At this level you should see a folder named bookmarkbackups among other things.

Select everything and Copy (either right-click > Copy or Ctrl+c).

Switch to the empty new profile folder in other window and Paste (either right-click > Paste or Ctrl+v). This may take a minute since some of the files are large.

Start Firefox

Firefox should start up in that new profile with the resurrected old profile data. Success?

By the way, to switch from the orange Firefox button compact menu to the classic menu bar, you can:

• right-click a blank area of the tab bar > Menu Bar
• right-click the new tab "+" button on the tab bar > Menu Bar