Firefox randomly opens websites, even when it is closed

Question

random websites pop up when I am idle, even if firefox isn't running

Answer 1

Did you download Firefox from the official Mozilla site? Sometimes if you search on Google or any search provider, they sometimes have "Advertised links" which are sometimes Firefox bundles that have been slightly modified/shipped with malicious software.
* https://www.mozilla.org/en-US/firefox/all/
If you did download from a different website and believe that to be the cause, you can report the link here:
* https://www.mozilla.org/en-US/about/legal/fraud-report/
Sometimes a problem with Firefox may be a result of malware installed on your computer that you may not be aware of. First check your home page settings to make sure nothing was appended (if there is a | followed by another link, that tells Firefox to open another tab with that link):
* Tools (or [[Image: New Fx Menu]]) > Options > General
Also check your add-ons for any suspicious extensions:
* Tools (or [[Image: New Fx Menu]]) > Add-ons > Extensions
Check your list of install programs in Windows - Control Panel > Programs and Features. Usually malware comes bundled with other applications, so if you sort by date and see several applications installed at the same day, it may be easier to find suspicious applications that way.
You can also check to see if your shortcut has been tampered with. Right click on your Firefox shortcut and select Properties. Check the target line under the Shortcut tab for any web pages after the "firefox.exe".
You can also try the Reset Firefox feature which can fix many issues by restoring Firefox to its factory default state while saving your bookmarks, history, passwords, cookies, and other essential information. Note: After resetting Firefox, you will lose any extensions, toolbar customizations, and some preferences. See the [[Reset Firefox - easily fix most problems]] article for more information.
You can try these free programs to scan for malware, which work with your existing antivirus software:
* [http://www.malwarebytes.org/products/malwarebytes_free/ MalwareBytes' Anti-Malware]
* [http://general-changelog-team.fr/en/downloads/viewdownload/20-outils-de-xplode/2-adwcleaner AdwCleaner] (for more info, see this [http://www.bleepingcomputer.com/download/adwcleaner/ alternate AdwCleaner download page])
* [http://www.microsoft.com/security/scanner/default.aspx Microsoft Safety Scanner]
* [http://support.kaspersky.com/viruses/disinfection/5350 Anti-Rootkit Utility - TDSSKiller]
* [http://www.surfright.nl/en/hitmanpro/ Hitman Pro]
* [http://www.eset.com/us/online-scanner/ ESET Online Scanner]
Further information can be found in the [[Troubleshoot Firefox issues caused by malware]] article.
Did this fix your problems? If not, try posting in a forum specializing in malware removal:
* Bleeping Computer - http://www.bleepingcomputer.com/forums
* Spyware Warrior Forums - http://www.spywarewarrior.com/index.php
* SWI Forums - http://www.spywareinfoforum.com/
Please report back to us!