The Reset Firefox feature can fix many issues by restoring Firefox to its factory default state while saving your essential information. Note: This will cause you to lose any Extensions, Open websites, and some Preferences.

To Reset Firefox do the following:

1. Go to Firefox > Help > Troubleshooting Information.
2. Click the "Reset Firefox" button.
3. Firefox will close and reset. After Firefox is done, it will show a window with the information that is imported. Click Finish.
4. Firefox will open with all factory defaults applied.

Further information can be found in the Refresh Firefox - reset add-ons and settings article.

Did this fix your problems? Please report back to us!

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 or otherwise make changes.

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

You can also do a malware check with some malware scanning programs on the Windows computer.
You need to scan with all programs because each program detects different malware.
Make sure that you update each program to get the latest version of their databases before doing a scan.

• http://www.malwarebytes.org/mbam.php - Malwarebytes' Anti-Malware
• http://www.superantispyware.com/ - SuperAntispyware
• http://www.microsoft.com/security/scanner/en-us/default.aspx - Microsoft Safety Scanner
• http://www.microsoft.com/windows/products/winfamily/defender/default.mspx - Windows Defender: Home Page
• http://www.safer-networking.org/en/index.html - Spybot Search & Destroy

You can also do a check for a rootkit infection with TDSSKiller.

• http://support.kaspersky.com/viruses/solutions?qid=208280684

See also:

• "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked

Since making my initial post I discovered the pop-up had to do with checking add-ons. To get rid of it I went back to an earlier version of Firefox, deleted and unchecked the box that appeared during the instal and the pop-up went away. I never saw the pop-up during the ver 16 upgrade.

I would be happy to upgrade to 16 again if I knew I would be able to avoid that function working on my system.

The only things I ever allow to update automatically are my security software such as Norton AV and WIndows Defender. Everything else is either set to Notify Only or turned off. I update manually or at least choose what updates to accept for everything else, even Windows.

What really ticks me off about the automatic stuff is every programmer seems to believe their product is the center of the cyber universe and it is essential to go out online looking for updates before one's system security software starts up.

Mozilla is no different in its belief that it knows better than we users what is important on our systems and what is not. In order to restore my preferred method for saving history I had to load an add-on to undo that function now built into Firefox. I considered the changes made to create the "smart" history function to be invasive. I feel the same way about the damn addon pop-up.

I do not save cookies, regular or otherwise, I block tracking software and I decide if so called upgrades really are and if I want to load them. I consider anything that circumvents that decision making process to be invasive.

So if somebody can tell me how not to have that add-on checker thing functioning in version 16, I will upgrade my version of Firefox. otherwise I will just ride it out using the older version

Incidentally, I am one of those folks who prefers to use multiple windows over tabs. By labeling the address bar as the Tab bar, you caused me (an many others) to resist upgrading from 3.6. Had I known what it really was, I would not have waited until your forced me to upgrade. Incidentally, I also dislike that when I click Help to get to this site that it does so in a tab not a new window the way my system normally works. My system is set to open links in a new window and it does so except for that. That is invasive as far as i am concerned.

The only way i could fix this problem was to remove ver 16 and reinstall 14.0.1. The in order to prevent Mozilla from asking me to upgrade all the time i had to reset Firefox never to check for updates.

I tried using ver. 15 but that has the same problem as 16.