I think I'm using Firefox 31.0 (How do I check?). I was on mp3clan.com, I searched for a song, when I clicked "Play" on the mp3clan webpage, it said I have to disable Adblock. I clicked on the Open Menu button on the top R, clicked on Add-Ons, checked Extensions, Appearance, Pug-Ins and Services, but I don't see it in any list. What's going on? Is this a trick to get me to download some kine of harmful software?