You have spyware. There seems to be a new trend of rogue websites doing 'drive-by' installs of spyware FF addons. Unfortunately you did not copy the entire list into your detail, so we can't see what you have. We need the entire list of Extensions from the about:support page. In my case, it was disguised as XULRunner (a legitimate FF extension).

Also, make sure your antivirus/antispyware is up to date and scan your system (however, these extensions will not usually be detected).

Do a malware check with some malware scan programs.
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 the database before doing a scan.

• http://www.malwarebytes.org/mbam.php - Malwarebytes' Anti-Malware
• http://www.superantispyware.com/ - SuperAntispyware
• 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
• http://www.lavasoft.com/products/ad_aware_free.php - Ad-Aware Free

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

There are other things that need attention:

Your above posted system details show outdated plugin(s) with known security and stability risks that you should update.

• Next Generation Java Plug-in 1.6.0_16 for Mozilla browsers

Update the Java plugin to the latest version.

• http://www.oracle.com/technetwork/java/javase/downloads/index.html (Java Platform: Download JRE)