that appears to be a virus.
another forum thread user at firefox's website suggested the following.
Do a malware check with a few malware scan programs.
You need to use all programs because each detects different malware.
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
Afterwards you may want to change your DNS on your router.
you can change your routers DNS by using the following link - it will give you step by step instructions
https://store.opendns.com/setup/device/actiontec-mi424wr/
open dns preferred : 208.67.222.222
open dns alternate : 208.67.220.220
google dns preferred: 8.8.8.8
google dns alternate : 8.8.4.4
Genuity Level 3 4.2.2.1 and 4.2.2.2 <~~ I like these ones - A lot of people like the OPEN DNS numbers. pick your poison.