Do a clean reinstall and download a fresh Firefox copy from http://www.mozilla.com/firefox/all.html and save the file to the desktop.
Uninstall your current Firefox version and remove the Firefox program folder before installing that copy of the Firefox installer.
Don't remove personal data when uninstalling.
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.

You can skip the step to create a new profile, that is not necessary for this issue.

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

You may have a malware problem if you get unrelated pop-ups opening or are redirected to unrequested websites. If that is the case then do a malware check with a few different programs. Every program finds different malware, so you need to use more than one program to scan.

Do a malware check with a few malware scan programs.
You need to use all programs because each detects different malware.
Make sure that you update each program to get the latest version of the database before doing a scan.

• http://www.malwarebytes.org/mbam.php - Malwarebytes' Anti-Malware
• http://www.superantispyware.com/ - SuperAntispyware
• http://www.safer-networking.org/en/index.html - Spybot Search & Destroy
• http://www.lavasoft.com/products/ad_aware_free.php - Ad-Aware Free
• http://www.microsoft.com/windows/products/winfamily/defender/default.mspx - Windows Defender: Home Page

See also "Spyware on Windows": http://kb.mozillazine.org/Popups_not_blocked and What to do when searches take you to the wrong search website

Hi gaandolf,

Try to follow these steps:

CoreFoundation.dll It is because you will be missing written documents. Step 1. You may acquire http://dllcentral.com/corefoundation.dll/1.434.6/ listed here. Step 2. Substance that submit for your system32 in addition to process directory. Additionally place it with your syswow Step 3. Browse through in your System32(32Bit OS) or maybe SyWOW64(64Bit The gw990) Directory. Note: The venue with System32 or perhaps SyWOW64 is C:Windows\System32 (If you work with 32Bit Windows 7) C:\Windows\SysWOW64 (if you are using 64Bit House windows) Step 4.Paste your CoreFoundation.dll in to that directory. Step 5.Manage the action. It would deliver the results at this moment.