How to get these flash ads (adchoices) OFF of my computer, particularly Facebook?

[Spenc787]

My computer used to be fine, with no ads at all. Then one day a few months ago I noticed these ads all over my Facebook. They're usually at the very top of my facebook page above a cover photo, then on both sides and in between posts. If I go to the timline live feed on the right side and hover over someone who has done something, the window pops up of their conversation and a freaking ad will be IN that box too. I have tried downloading FireFox's adblocker thing. And that works, BUT there's still a huge blank space where all the ads would normally be. The ads are coming from AdChoice. I've tried to opt out of getting ads from them but it still isnt working. I want my mac back to normal! How do I make this crap stop? It is slowing down my web browsers. Facebook is constantly loading. In between ads changing I cant type because it's like the browser goes into overload and freezes until the new ad comes up. SO annoying. PLEASE help.
But no one else has these ads on their facebook or other webpages. I've asked all of my friends and they thought I was nuts until i sent them a screen shot.