Annoying Embedded Ads in Firefox, how to remove them?

Dear all,

Starting yesterday, I found that there are annoying embedded ads displaying frequently when I am using Firefox(see the screen capture below)!
https://dl.dropboxusercontent.com/u/3418382/tmp_forum/Annoying%20Embedded%20Ads_in%20Firefox_2014-03-07.jpg

Does anyone know what adware I have infected?
→ and how to kill it?

Thanks for any kind of help!

Please attach your logs. (MBAM, OTL and aswMBR…!!)
Instructions: http://forum.avast.com/index.php?topic=53253.0