I hardly recommend reinstalling mozilla. This may be caused by installing Firefox from a unofficial source. If you still have the problem, please report here.

I downloaded the update from Mozilla.com itself!

I still recommend reinstalling mozilla.

Thanks for the help. Will reinstall and let you know what happens!

If you download Firefox from the Mozilla server that there won't be any malware or viruses included, so make sure that you only download Firefox from the Mozilla server.

You can find the full version of the current current Firefox release (39.0) in all languages and all operating systems here:

• https://www.mozilla.org/en-US/firefox/all/

If you get a pop-up message asking to update Firefox or plugins or scanning for malware then such a message is likely a scam and you should never respond to such an alert to avoid getting infected with malware.

• Only update Firefox via "Help > About" or by downloading and installing Firefox from the Mozilla server and never via a pop-up or link on a web page.
• Plugins should only be updated via the plugin itself or by visiting the home page of the plugin.

Note that some security software detects malware in the small stub installer that downloads additional files from the Mozilla server (i.e. a false positive) and you should contact the developer of your security software about this.

Do a clean reinstall and delete the Firefox program folder before (re)installing a fresh copy of the current Firefox release.

• Download the Firefox installer and save the file to the desktop
  https://www.mozilla.org/en-US/firefox/all/

If possible uninstall your current Firefox version to cleanup the Windows registry and settings in security software.

• Do NOT remove "personal data" when you uninstall your current Firefox version, because this will remove all profile folders and you lose personal data like bookmarks and passwords including data in profiles created by other Firefox versions.

Remove the Firefox program folder before installing that newly downloaded copy of the Firefox installer.

• (32 bit Windows) "C:\Program Files\Mozilla Firefox\"
• (64 bit Windows) "C:\Program Files (x86)\Mozilla Firefox\"

• It is important to delete the Firefox program folder to remove all the files and make sure that there are no problems with files that were leftover after uninstalling.
• http://kb.mozillazine.org/Uninstalling_Firefox

Your bookmarks and other personal data are stored in the Firefox profile folder and won't be affected by an uninstall and (re)install, but make sure NOT to remove personal data when you uninstall Firefox as that will remove all Firefox profile folders and you lose your personal data.

• http://kb.mozillazine.org/Profile_folder_-_Firefox
• http://kb.mozillazine.org/Profile_backup

• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Clean_reinstall

No version of Firefox for Windows, Mac OS X and Linux from mozilla.org has ever been proven to have a virus or trojan or any such. There was one case back during Firebird 0.6 or so that a contributed locale build was apparently infected as Firefox 1.0 was the first Release to have other languages officially.

A few antivirus clients may give a false positive shortly after a new Major version and they then fix it in a new definition update in antivirus.

As said some antivirus clients still gives false positives on the stub installer (Windows) even though it has existed since Firefox 18.0

If Firefox 39.0 on Windows was indeed infected, it would be a VERY hot topic here, at the independent forums.mozillazine.org and various tech sites around.

agucova said

I still recommend reinstalling mozilla.

This web browser is Mozilla Firefox or Firefox for short. The name Mozilla for browser used to refer to the old Mozilla suite (1.7.13 was last) until Mozilla stopped development. The community then continued the suite as SeaMonkey.

Thanks for all the help and the awesome info! It is good to know that some companies still honor a code of ethics on the internet in a world of "take advantage of the disabled". Seriously, I have learned much needed info about firefox and have been using them for several years, I would never switch! Tried Google and had more issues with them than I care to list, but I have worked with Norton Securities since the late 80's I would never get rid of them.

Norton has been one of the ones to do false positives with Firefox before over the years.

Norton has done it recently with Firefox 39.0 in claiming Suspicious.Cloud.9.B. Though it seems to occur more for the EOL Windows XP users. ex: https://support.mozilla.org/en-US/questions/1065074

edit: turns out it may have been more widespread in this case https://community.norton.com/en/forums/suspiciouscloud9-over-100-false-positives-morning

Also if a antivirus claims something in Cache is infected, it is harmless while it is in the Cache.